My 30 year old Trek 520 touring bike has a 7 speed rear (3 rings up front) and brifters - controversial on a touring bike back then.
The past 7 years that bike has been doing Zwift duty in the basement on a wheel-on smart trainer - a fairly benign environment but lots of miles and not much shifting.
I did a very hilly ride on Zwift and had to use the big ring in the back - and the brifter for the rear died, couldn't get off that ring. Cable was fine, tried soaking in WD40 (that had worked years ago), no joy.
Took it in to bike shop, they found inexpensive MiroShift 7 speed shifters and replaced. They seem to work pretty well, but on my 3 different bikes I now have:
- Trek 520 3X7 with Microshift double paddle shifting
- Jamis Renegade with SRAM 1x transmission and "double tap/long push" shifting on one paddle one way.
- Trek Domane 2X with Shimano traditional brifters
The first ride on each bike involves some fumfering for the first few shifts...