Consistency is important, especially with microloaded lifts like press and bench. By that I mean, if you have multiple pairs of 45s, make sure you're using the same ones for the pressing movements. I have a rag-tag collection of plates that I've acquired via craiglist/fb marketplace over the last few months. Finally borrowed a parcel scale from work and weighed all of them. Two of the old school 45s are dead on at 45, two are around 44 3/4, but the two Fitness Gear plates are dead on at 46. That's worth knowing when I'm increasing my press and bench by 2lbs. I have three pairs of 25s too and two pairs are in the 25 1/4 range but one pair is 26 1/2. Fortunately each pair is pretty close to each other. All are marked now and I can load my presses accordingly.
Speaking of fitness gear, the 45s are under 15 1/2" in diameter, so buyer beware, as they are semi-available at retail now as well as the secondary market.