Ask HN: When do you replace your Macs?

I have a 2015 MacBook Pro whose batteries have started swelling up lately. It's not covered by the recall, so I have to pay out of pocket. I've been thinking of a few options:

1. Get a new one. The old ones is six years old, hot, noisy and struggles with external 4k monitors. I've heard good things about the M1 here on HN. But it's rather expensive and wasteful.

2. Get the batteries replaced. It's only 10% of the cost, and a lot of the other problems can be fixed with a pentalobe screwdriver and a can of computer duster.

3. Do nothing and risk burning down the house. I have no clue how big the risk is.

What are your replacement strategies?