Generally options are rolled either up (for calls) or out. Puts are rolled either down or out.
I roll as a defensive measure. If I am short a 100 strike U call and the market has moved adversely, I might roll up by buying back the short 100 and maybe writing two 110 U calls. This increases my exposure but moves the danger area higher. Could also be seen as a form of averaging down. Ie, the market may trend adversely longer than one has the margin to roll.
Rolling out is the same thing except you roll out in time. If I was short a 100 strike U call and wanted to roll out, I might buy back the short U and maybe write something in the V or X or Zs.
I generally prefer to roll up rather than out.
I hope this helps and I hope you hear from others as well.
Peace and gtty,
Lar