[VAC] stabilizing jacks

[Asdf1009@xxxxxxx]

Hello, again - 

Another newbie question.  In reading about travelling with a travel trailer, 
I read that one should use stabilizing jacks when setting up camp.  Here's my 
question -- are they necessary?  If so, where does one put them, so as not to 
damage the trailer? And, as there are different kinds, what type do folks 
prefer?

Thanks,
John, who sometimes thinks it might have been easier to buy a new trailer!