I fall in and out of interest with my Audi, its been a project that long now going on 3yrs that its bound to happen, i just leave it when that happens and within a few weeks or months, something sparks my interest again, usually seeing a nice car in a mag, on the road or watching Top Gear hoon some cars about.
Ive considered selling a couple of times but know i would regret it, unless you have a solid interest in whats going to replace it!