My advice - never sell or dispose of a lens. Murphy's law applies here. The moment it is gone you start berating yourself for having done it! I have 2 Summicron 90's - both v II, an Elmarit 90f2.8 vI, collapsible 90f4, Apo-Lanthar 90f3.5 and a 105f2.5LTM ( and that is only in M/LTM system) - and I am not even that big a user of 90 mm lenses!!! Only 90 that I did get rid off was a 90f2 AA as i did not like it, and I did have an Elmarit-M 90f2.8. Did not use it much and lent it to a friend as a long term "loan" - If I get the urge, I can get it back - though that has not happened for the last 5 years!
Oh, forgot the Canon 85f1.9 and a Jupiter 85f2!