Was assuming that you're buying used?
If so, I'm telling you - always get the car checked - garage or not.
Without going into detail, Carcheck discovered some important faults for me in the past - on cars from a garage, that seemed fine with NCT and warranty etc.
Faults were enough to make me change my mind about buying. Sometimes the faults were minor sometimes more serious but regardless, in my experience, it also indicated that the sellers in question had blatantly lied about specifically asked questions.
I would never by a used car from anyone without having it independently checked
Garages will usually only provide up to a years warranty on used cars - sometimes less. Plenty of hidden problems can arise after the year.
Buying used always has some element of risk but I think Carcheck or someone similar is well worth it.