When going to get professional photos taken, what are the different combinations

Question: When going to get professional photos taken, what are the different combinations one sheet could consist of

This is the forth time I've done this w/ my son, you'd think I'd remember by now!. Anyway, I just like to be prepared when I go (especially since my husband's joining us this time and he has no patience!)!. That way when picking out the package I want, I can show the photographer exactly what I need and in which sizes!. For example, obviously one 8X10 can fit on a sheet and I think 16 wallets, but what other combinations can I do!?Www@QuestionHome@Com

Best Answer - Chosen by Asker:

A unit is anything that can fit on an 8x10 paper!.

so: 8x10

OR (the basics that are usually offered)
2-5x7
4-4x5 (3!.5x5)
8 wallets (2!.5x3!.5)

AND (labs can print this way but most studios don't offer it)
1-5x7 and 4 wallets
1-5x7 and 2-4x5 (3!.5x5)
16 sub wallets (the tiny ones kids get with their school pics)

Www@QuestionHome@Com

Most print using the following formula:
One "unit" =
1-8x10
2-5x7
4-4x5 or 3-1/2 x 5
8- wallets (2-1/2 x 3-1/2)Www@QuestionHome@Com