pairs, trios and other such groups?

Did you ever send an apprentice to the stores for a long weight by any chance?

Blocks and strips are collected for many reasons and it depends upon the collector for the reasoning.

'Plate blocks' are generally collected in as many stamps wide as the sevedge has notations.

Strips are often collected as examples of coils and for the numbers printed on the reverse.

Used blocks are often collected because they show entire postmarks. If the stamp is not the reason for display then the orientation of the stamp is irrelevant.

In many cases specialists who study a single area or produce work like Brixtonchrome's on the Canadian caricature issue, collect blocks to ascertain the position on the sheets and to find the minute details.

As to value, yes to a degree a block is more expensive than singles, but it all depends on the stamp itself and the degree of determination of a collector to acquire it.

Seperating blocks. The last known entire sheet of penny blacks was sold to a dealer who promptly cut it up to sell as blocks and singles because no-one could afford to buy the entire sheet.

Mostly it comes down to personal preference.

Your 5.2c sleigh coils show a particular feature of American coil stamps that is very collectible - the Scott US Specialized Catalogue will list the coil line pair (that's the leftmost pair of stamps with an ink line down the middle of the perforations). This line pair only occurs at the joining line on a rotary printing plate (the ends of the printing plate sections when they're wrapped around its cylindrical base), as ink gathers at that joint. Well, strictly speaking that's not true, as some coil stamps have intentionally inscribed lines engraved into the plate, but what you have is a line formed by the joint. These coil line pairs are obviously less common than regular coil pairs (which are also listed in specialized catalogues). And in your specific example, you can see a tiny plate number on the very bottom of the stamp to the left of that ink line. These are also highly collectible - have a look here for the Plate Number Coil Collectors Club.

Some other stamps are intentionally kept as pairs too, but sometimes you need a specialized catalogue to spot that. Swedish booklet pairs are listed in Facit and German defintive horizontal pairs from after WWII are listed in Michel. For whatever reason, the smaller sized German definitives have had printed albums created for horizontal pairs and sometimes the values seem a bit crazy - some old Heuss definitive horizontal pairs can be worth more than 100 times as much as the exact same stamp in a vertical pair. Whatever!

Ryan

thank you all! I noticed the line on the 5.2 sleigh stamps, but didn't really think much about it. These were grabbed at random from the "recently soaked/still to be sorted pile"

always a learning process here (I love it!)

and Feebletodix- never a long weight, but yes, instructions to go find  left handed nails and board stretchers ;-)