Repair or replace is a question about the next two years

The right comparison is not what the machine cost, it is what it still has left in it.

Owners usually approach this decision backwards, by thinking about what they originally paid. That figure is gone and it tells you nothing about what to do now. The question worth asking is narrower and more useful: if this repair works, how long will the machine keep doing what I need, and would that money buy more time elsewhere. A modest amount spent on a machine with several good years ahead is excellent value. The same amount spent on one that is close to the end buys you a few months and another decision.

The second half of the question is about what you actually do. A computer used for correspondence, photographs and watching things has very different demands to one running demanding work, and machines age out of those two roles at completely different speeds. A computer described as too old is often perfectly adequate for the person using it, and the label came from someone comparing it to what is on sale rather than to what is required.

There is also a real cost to replacing that nobody quotes: the afternoon or the week of getting a new machine to feel like yours again, and the risk to your things during the move. That is not an argument against replacing. It is an argument for making the decision deliberately rather than in frustration on a bad morning. Frustration always votes for a new machine, and it is not paying.