I do this for most everything I buy, with the research time spent proportional to the price. This cuts waaaaaay down on impulse buys.

Something will sit on a list or browser bookmark library for days to years. If I see that something has been on a list for a "long time" ("long" being relative), I recognize what was potential "retail therapy." Sometimes I delete it from the list, sometimes I leave it in case I get the same idea sometime in the future. Seeing it there reminds me I already decided I don't need "it."