I intended to say that it's probably been equally long since I completed an MM6 game! I tended to reach the middle of a game and then get overtaken by events and lose track of my overall plan for the rest of the game.
I'd virtually completed a World of Xeen game when I abruptly ran out of money – I'm going to have to go and mine some gems and get some expensive armour made to build up my exchequer again – and at present I'm about half way through MM3 again.
Also, my vintage desktop expired about a year ago, so I'll have to get out my old laptop before I can play MM6 again. I'm a bit short of disk space on this one.