I heard it wasn't good to put cars on jacks for long amounts of time... it strechs the springs/coils and allows them to rust easier. But that'* just what I heard.
No that'* just not right. What a load of crap.
The spings are still slightly under compression even when jacked. If anything it is better because they are under less compression and therefore won't sag as much.
BTW it has only been up there for two weeks.
My other car, 79 Firebird which I also bought new, has often been up on jacks the entire winter season. No problems and still running with stock springs.