Advice please - Car stuff

Fix the car. My sis in law had a W reg Vauxhall Astra worth £150 on a good day. 2 months MOT left and clutch went a few weeks ago. Told her to put it through a MOT and find out what it failed on and how much a clutch would be. Well it went straight through the MOT and passed with a few advisories, clutch replacement was going to be £300. My stupid sis in law decided to ignore my advice, not to put a new clutch in her £150 Vauxhall Astra because it was going to cost £300 and instead go and buy another car. She found a cheap Corsa, the week later she found out why it was cheap as it ended up in the garage having to have a few hundred quid spent on suspension work.

Better the devil you know. I'd not think twice of spending a grand on a car in a year on none servicing repairs because I know the history of the vehicle and that grand spent is likely to be on things never needing replacing again before it ends up in the scrapyard. If I'd sold my broken car I'd not get much for it and the £1000 I saved on repairs and used to buy another car would only buy me something most likely to have its own set of issues needing fixing in the next year or so but I'd have no idea what they were when I bought it.

The other thing people overlook when deciding to get a new(er) car to save repair bills on their existing one which may cost more than it is worth is depreciation. I bought a 2010 Mondeo at 2 years old for £8500, just 1/3 of its new value. Today its worth around £2500. Depreciation alone has cost me £1000 a year and only because I managed to get it dirt cheap and kept it over half a decade. Get a car of an age and mileage where you're most likely not to have much in the way of repairs and £1000 a year or more is the kind of depreciation you'll be looking at simply for owning the car. All of a sudden that £200 repair looks cheap in comparison.

Personally I've never understood how spending £1000s on a newer car to avoid repair bills in the £100s on their current one makes sense to anyone.