Really depends on a few things:
1) Do I REALLY LIKE, yep, REALLY REALLY like the figure? If yes, then
2) Is it a character that I REALLY like? If yes then
3) Do I want more of this figure to cusomize? Yes/or No then I go to
4) Do I have the money in my budget to do this? If yes then
I buy it.
For ROTS, I have mutiples of the Obi Wan Pilot x5 {not inlcuding the one my son has(best figure IMO in the line, or you have to include it in your top 3)}, one of the brown mask AT RT and one of hte white Mask AT RT, Five Shocktroopers (they grew on me after my son opened his and I want a squad for a diarom. I want to make of the senate scene after the Yoda/Sidious fight);
Three Agen Kolars, one to keep, two to cusomize. Two AT TE to display and 3 to customize; 2 #41 SA Clone to keep, 8 to cusomize. A few others.
The main one is the Obi Wan Pilot. I too have one with robe and one without.