I have a 1993 toyota corolla wagon DX. It has only 45,000 miles on it but needs a new radiator and front brakes at a cost of over 600 bucks. Is this worth it? I think the car should keep going for another 50,000-75,000 miles so say "yes’ what are your views?
Only 45.000 miles? This thing will probably outrun you! If you are happy with the car and there is no other problems with it, I think it’s a no brainer. Unless you want an excuse to get a new car of course 
But, changing radiator and brakes is fairly easy, so if you do it yourself you can probably save about 400 bucks
Are you kidding? This car could probably go another 200,000 miles. Unless you hate it you really ought to fix the radiator and service the brakes. Brakes are a wear item and not technically a repair. You have to expect to replace pads and rotors occasionally. Like changing the oil or replacing tires. The radiator is more of a repair. Unless there is a lot more that needs replacing or fixed, you clearly should spend the $600. That’s less than 2 car payments on a new car, and about 1/4 of what buying a replacement used car would cost.
Yes.
Your mileage goal of another 50k-75k is realistic. Realize this car will require maintenance and repair which the items you list are to get there.
$600 is nothing when it comes to maintaining your vehicle. These are fairly minor repairs (in the scheme of things), especially the brakes. Any car would require this kind of work on a semi-regular basis. Plus, your talking about a Toyota; you could get another 200k at least on it with proper maintenance. Sounds like a no brainer to me, this car is barely broke in.
on the bad side:
with such low mileage this car is going to have other issues relating to rust, or stuck parts, or deteriorating rubber gaskets, hoses.
remember at this age this should have around 200,000 miles on it, and it has obviously been sitting around in a grandmothers garage somewhere!
all in all, thses items will cost less to repair than to buy a new car, so it IS worth it, but just be aware that there ARE going to be issues which will pop up as you start to use the car.
Cappy makes an excellent point. While the car has many more years of life left, at this age it would be a wise move to carefull go over everything that is made of or contains elastomerics, including those things like the brake system. Replace all the practical items like belts…including and especially the timing belt, hoses including vacuum hoses and radiator hoses, and carefully inspect the brake system for signs of leakage, stuck calipers, and corrosion of lines and fittings. A servicing of things containing fluids may be wise also. Sedimentary layers can form in spaces with fluids when there’s no turbulance to maintain their suspension. Yup, I’m thinkin’ tranny…but be sure you get that doen at a qualified shop.