Yeah i am pretty much the same, funnily enough the 350 was probably the longest i had a car for a quite some time and only changed to a supercharged one because i just couldnt say no to the price.
I find i change for a few reasons, my driving habits change, i.e wanting to spend more time at the track or road, finances have allowing the purchase of something previously out of touch or depreciation brings something into budget, or simply something catches my eye that previously i hadnt even entertained and thought i should have one. I have even got out of one thing into another and back into what i had before because it wasnt as good as you thought. You are a long time dead, enjoy whatever you can, when you can.