When is it time to buy a new (at least new to me) car? (Illinois)

I have a 2012 Honda Civic LX Sedan. It currently has 160k miles on it and in the last 2 months I've put about $1500 in repairs into it (Emissions issue, software update & gasket replacement on engine). It's hard to know if these repairs that have happened 6 weeks apart are going to make the car have chronic issues, but with it being 10 years old who knows. I also was hoping/planning to drive this thing into the ground at about 250-300k miles.

Anyway, my wife works remote and we barely drive the two cars we have. The only time I drive this car is when I'm going into Chicago (from the burbs) on the weekends for work.

The car is valued around $4,000. And other than these recent $1500 in repairs, it hasn't needed anything out of the ordinary, except for normal stuff like tires, brakes etc.

At what point is it time to ditch the car and go with something more reliable? It's still a reliable car, and I would much rather prefer to pay $1500 in repairs than go buy a $20k used car, but when do I know it's time? When the transmission goes out? When the next repair costs more than the value of the car?