Originally Posted by Dave Mayer

I have around a dozen bikes (all good) with cassette counts from 7 to 12. Today I was using an Emonda SLR with a double shifting with Dura-Ace Di2, which operates very well indeed.

However, the bike I use the most is a 1991 steel MTB with 26" wheels, no suspension and a 3 x 7 Shimano drivetrain with the legendary XT thumb shifters. I've also been spending a lot of time on a Lemond with a 3 x 9 Campagnolo drivetrain. Also excellent.

It's all good. Tune what you have, and do the usual cable and housing replacements, new chain, replace worn cassette cogs etc. 90% of the problems we see at our Co-op are simple maintenance and solvable by replacing consumables, resulting in drivetrain performance that is good as new. Or often better.