In terms of chain longevity, tensile strength, and performance FOR THE MONEY the Shimano Ultegra chains are the right mix. So I always go that way, but certainly if one of those three things are of oursized importance to you you can go a different way. Definitely you can spend a lot of money on performance chains if cost is no object.
Depending on what you are doing with the bike my advice is to change the rear cluster, chainrings, etc AS NEEDED. If you put on a new chain and ride the bike around for 50 miles and experience difficulty shifting or chain skipping, then change out the cassette. Otherwise, don’t fix a problem that doesn’t exist. On the other hand if performance is of primary importance put new cassette and chainrings on.
