How do you decide when to use a mount or use a hinge?

For countries where I have albums or pages, I would use hinges for most stamps. I would reserve mounts for MNH and for high-value stamps, so that those would pop out on the pages.

For early France, I found that sometimes the color rubs off onto the facing page, especially for type sage. All stamps from that period I now use mounts now matter how common the stamp.

Nowadays I mostly use Vario pages, and am running out of hinges.

Me too - plus Hagnar. I swear in the long run it is cheaper than albums and mounts. 

I use custom made pages, so much the same as others:

All MNH go into mounts (mostly black, but sometimes clear), as does anything with a CV over £3ish, everything else is hinged.
Any blocks or sheets or se-tenants are usually hinged to avoid having to find a mount big enough.
I print my pages with a 4mm black stamp border so it's sometimes impossible to tell at first glance which is which on the page.

Everything is in mounts. Early on I thought I would only use mounts on mint stamps, but in some cases there would be one or more in a series that was out of reach mint and to have some mounted and others hinged just didn't look right.

but, whatever works for you is perfect!

I only use mounts, never hinges. Virtually all hinges made these days are garbage. I still have an unused box of 1000 hinges from Honor-Bilt sitting on my desk and a box of Dennisons packed away somewhere, but I'll probably never use them.

Agree.....if a stamp is worth "mounting" in a special catalog......why not mount it - "hinging", for me, are from old albums received from my late dad -

René

Most of my opinions are from the point of view of someone who likes to buy collections. 

Hinges are very problematic. There are no peelable hinges on the market so if you buy a hinged collection, you either have to soak off the hinge or keep a hinge remnant. Hinge remnants can bow the stamp if they are thick enough. And no matter how careful you are when you remove hinged stamps from a page you run the risk of damaging one. Buyers tend to pay much much less for hinged modern material, but you do expect to see classic pre-1940 collections hinged - no choice there. So if the stamps are very common, if their loss would not be important to philately and if you don’t care about resale value then hinges are fine. 

Mounts are better for the stamps, but if they encase the stamp then they are a pain to a buyer. Here the resale value of the album comes into play. Since you have to slit the mount to remove a stamp, using mounts like those in a high end album isn’t the best. But if you could care less about resale then it doesn’t matter. Be careful using slit back mounts. I see so many mint stamps with damaged gum where the gum was moistened when the collector applied the mount. Also, it is almost impossible to examine a stamp that is cocooned in mounts. So, again, if you don’t overly care about resale value and you never want to change a stamp in a mount for a different stamp and you’re not worried about a tiny bit of gum damage then slit back mummy mounts are ok. The open top mounts like in the premium hingeless albums are really nice though. If your collection is semi-static then mounts like those are nice.

A third option is to ditch hinges, mounts and albums for Vario and Hagnar style pages. The pages themselves actually have resale value whereas albums that had hinged and mounted stamps usually get tossed in the recycle. In my experience they end up being cheaper than albums, binders, supplements and mounts. Check out the latest Vance auction and they have starting estimates of almost a dollar a page for used black stock sheets. If you are like me and you are constantly adding and changing stamps, upgrading quality and cancels, have multiple copies of different issues and collect both mint and used, then loose leaf stock sheets are the way to go.

The most important things are to protect the stamps for future collectors and to enjoy your collection. Do what makes YOU happy, eh? 

Hinges have done so much harm to stamps I only use clear Showgard mounts.  The stamps are protected from accidental harm as they are encased to that mount.  They don't leave a mark if you take the stamp out of the hinge for whatever reason.  They are in the same condition as when ou put them in the mount.
Nick

I stopped using mounts and hinges a few years ago, because I found that I didn’t enjoy the process.

But I do enjoy laying out the stamps and displaying them, so I switched to Hagner sheets as an experiment. I liked it so much that I have not mounted or hinged a single stamp since then.

But I agree with the idea of “to each his/her own” and I understand why others choose differently than I have.

My main collection USA is all put in my albums with black split back mounts. I never ever adhere the mount in the album with water, I glue the mount in. My albums are not expensive albums so yes if the mount is taken off the page the page will probably be torn but the stamp is always in the MNH condition that it was put in the album as. Probably 10% of my collection is used classics and they also are mounted the same way.
For my other collections they are in verio pages.

Of course mounts are better for preservation of stamps, in general, but I don't see any mention of the fact that mounts add massively to the thickness of any album. A mount is twice as thick as a stamp. Adding the stamp inside, makes a mount as much as three times the thickness of the stamp. This quickly becomes clear to anyone who has filled an album with stamps in mounts -- the album bulges out enormously. Stamps alone also make albums bulge, but mounts double or triple the bulging problem. That means you need another binder (or two). And so what you thought would be a one-volume collection becomes a two-volume collection -- or three volumes. Scott binders cost $50, but other manufacturer's binders are even more expensive. I have a lot of multi-volume country collections that are now up to two or three volumes per country. Without mounts, they would be only one (maybe two) volumes. 

Stamp hinges largely avoid the worst of the "bulging album" problem. Not entirely since every stamp adds thickness to pages, but much less than mounts. Since mounts triple the thickness of every page in your album, this may be one reason for continued use of mounts -- besides their being much less expensive.

Hinges are also easier to use. Just moisten and apply. With a mount, you need to measure (or put the stamp into the mount), then cut it to size, then moisten and apply. As a worldwide collector, I can mount pages with hinges in no time at all compared to using mounts which take much longer. If time matters to you, which it may not.

Besides avoiding the worst of the bulging album syndrome and being easier to use, hinges have another advantage. Screw up the position of a hinged stamp? Wait until the hinge is dry, then remove it and redo. Easy. With a mount, that mount is likely there permanently at whatever odd angle you added it. 

What about cost? Cheap mounts -- which I NEVER use -- cost as little as half a cent per hinge. This must appeal to a lot of budget-minded collectors. A mount costs significantly more than a cheap hinge, about $0.07 each -- more than 10x the cost of a cheap hinge. If you're on a budget, that starts to add up fast. Consider: if a single country collection has 3,000 stamps (the U.S. is quickly heading toward 6,000), then mounting a full collection would cost only $30 for hinges. With mounts, that same collection would coast $210 to mount. For one country, maybe that's not so bad. But if you have 10 collections, you'll  be spending $2000 for mounts -- compared to $300 for hinges. I have more than 50 albums (How did that happen?), so feel free to do the math on that -- and then maybe go lie down for a minute. It's certainly not cheap to use mounts -- even if they are better. For smaller collections, the cost difference probably isn't a big deal, but for large collections, it can run into thousands of dollars. Most collectors might prefer to spend that large amount of money on stamps instead. 

Buying older quality mounts like Dennison's is more expensive than new mounts, but I think it's worth it if you can find them. Old packets of Dennison's currently seem to be selling for as much as $30 a pack (yes, unbelievable!) which is $0.03 a mount -- much more than the price of a cheap 1-cent or 1/2-cent hinge. Mounting those 3,000 stamps with these old high-quality hinges will cost more like $90 -- but still well under the $210 cost of mounts. 

Okay, the math is over (!) . . . . Anyway, here's what I do - and why I do it.

1. I nearly alway use hinges for stamps that are already hinged. I use only older quality hinges like Dennison's. I don't wish to do any further damage to my stamps. There's really no harm in re-hinging a previously used stamp if you use an older removable hinge. As for modern hinges, they are all absolutely awful and will always damage any stamp they are used on. I never use modern hinges.

2. My 38-volume Scott International albums get only hinges (the old kind) mainly to avoid the bulging binder problem but also because this part of my collection is mostly used stamps. I also hinge the unused stamps because many (most?) already have hinge marks on them anyway. To use mounts in an International album -- probably any large worldwide album (yes, there still are worldwide collectors!) -- would make each volume bulge out so enormously, you'd have to at least double the number of volumes you're using. My 38 volumes would become 76 volumes -- and that would cost me roughly $2000 just for all the new binders. I haven't even figured out what all those mounts would cost, but it would add many thousands more. 

3. In my single-country albums, I use stamp mounts for all mint stamps, and I use hinges for all previously-hinged used stamps. This means the early years of any country are mostly hinged (mainly Dennison's again) but, after the early years, it's stamp mounts exclusively. With dozens of albums, using only mounts would end up being prohibitively expensive, and they are unnecessary on previously-hinged stamps as long as I use ONLY the older hinges like Dennison's -- which I do exclusively. The only exceptions are much newer countries where there really aren't any (or many) older stamps. For those, I used mounts right from the beginning. 

As for Vario and other stock pages, I find stamps mounted on these pages move around too much for my taste. I also don't like so much plastic everywhere in my collection. To me, it just doesn't look good. I don't even like vinyl-covered binders very much. I do use Vario pages for covers since covers mounted on normal album pages seem too heavy for the paper unless it's unusually heavy paper. 

Have fun!