'Nuther cropping question

[dtscds]

I have read several cropping threads but still have a question:
I want to crop some of my stuff to upload to my online Smugmug account. Should I crop to a specific size/ratio (4x6, 5x7...) or can I just crop it to any size that makes it look the way I want? (i.e. 11.7 x 6.4, 9.3 x 8.5 or some such)
When someone orders a print I have a few days to get the final copy ready for printing--time for post-processing. So, this is mostly concerning uploading to the gallery.
Now, when it comes to getting them ready for printing, I assume at this point I should end up with a "standard" size. Assume that someone orders a 4x6 and 5x7, should what I upload be the exact size ordered or can I just upload something like 8x10 and let the lab do the rest? In other words, should I upload a different file for each size ordered?
Bring back film! Life is so much easier with fewer options!

[Debbi]

I personally would not let the lab do the cropping for your customers. it's worth the time to upload the specific size cropped the way you want it.