10IUs will never go bad. Let's say you start off with 1IU/day. You will continue that for the first few days, every day, and then increase it to 1.5 and then 2IUs.
After few 3-4 weeks you can switch to eod schedule @ 2IUs. Within 10 days the vial will be gone. When reconstituting, use bw water and that is good for at least two weeks. So, even if you start off with 1IU/day, you wouldn't start off eod, but rather every day. You will never go past two weeks on a vial, so no worries.