How long do you guys keep your iPhones for?

I’ve had an 11 pro max since 2019, and the battery health has now degraded to 79%. Bought it used for $1,400, if I sell it now I could salvage about $500. Or if I replaced the battery ($119 cad), I could probably get another 2-3 years out of it, although i would not be able to sell it for as much as now obviously. I’m just wondering how long you guys tend to keep your phones for, and whether it would be smarter for me to sell now and upgrade, or hold onto it for longer, but essentially lose all salvage value?