I have always left shifters alone until they play up, perhaps this is my mistake. I’ve got another 4 bikes with 105, Tiagra and Sora, the rest of them do far less miles as they are for my wife and kids, but I now wonder if I should be squirting something in to the levers as preventative maintenance.I have three bikes with 5700 shifters, after a ride I have them upside down on the bench, I always squirt GT85 into the levers, down the gear and brake cables with a squirt on the deraileurs, everything is functioning as day one.
If you are going for 11spd don't bother going to 5800 go to the latest version R8000
Because they spend time having to clean it up.Don't know about Shimano, because they are 'non-repairable' but when I sent in a set of Campag ergos for service/repair the company said the white spray grease I'd used was "not helpful"
Helpful for what purpose; and for whom?new and squidgy white grease is very helpful.