Life Expectancy 935 and battery

Well, my 935 turns 5 years old this month and recenltly I have had more blank screens and BSODs than befoer and it goes through the battery faster.
But the darned thing always comes back.
I am debating on replacing it with a Vivoactive 4 [which should be adequate for me in terms of features]
Any insights on the actual life expectancy of these things?  It is tempting to buy a new watch on the other hand...........