How old are your winches? Are they self tailers? I've had winches up to 40 years old and they weren't "worn out" - they just needed servicing and a few springs & pawls. I've never even had to replace a bearing, let alone a gear.
I've never seen a winch wear out, only fail from misuse and/or abuse.
If you have to go for store bought new, I'd go for S/S Andersens, no question.
I haven't used Harkens but the current Lewmars are only "easy to service" in that they don't require a tool to get the drum lock nut off - they are a sort of thumb screw with a head somewhat like those "security" screws they use to assemble public restroom stalls, only a lot bigger.
I don't know exactly how old the winches are. The boat is an '86 and I'm the third owner. The PO only had it a few years so I'm guessing the original owner replaced some or all of the winches. Maybe one is original, I don't know. They are all self-tailing.
Are Andersens worth the extra cost? Is the SS better than chromed bronze?