The stakes aren't as high with things that don't fly, of course – but it's still sound policy to do a "pre-flight" check of any car that isn't a relatively new car – and especially if it's a vintage car that only gets taken out every once in awhile.
Because in-between, things can run low.
Most cars made before the late '90s do not have tire pressure monitors – which you really shouldn't trust without verifying, either – so it's up to you to monitor the tire pressure. The older the tires the more likely they – or the valve stems – are leaking, even if it's only a little.
But being down 15 pounds on the right rear can dramatically change the way your car handles – and brakes – and not for the better. It also increases the likelihood of a tire failing due to friction and heat build-up.
Besides checking tire pressure – manually, with an accurate gauge – it's a good idea to check the tires themselves for signs of dry rot, such as cracks on the sidewall or bulges on the sidewall; the sight of either indicates a tire that is need of being replaced before you drive the car.