Sanding - how smooth is smooth?

[jbox]

After tearing off all the peeling dregs of once-glorious artwork, I now face the laborious process of sanding every stripped surface of the thing. Not having done a lot of woodwork before, how smooth is smooth?

Basically, the colour of the wood lightens pretty quickly, and I stop feeling residue after about 10 - 15 mins on a new sheet of 60G. Do I then need to go over it with a 120G sheet, or can I stop once my fingertips are basically happy (they're pretty good fingertips - no manly work callousing them)?

And a related question, how likely is it that I am going to notice any differences in surface depths after painting if some sections get more love than others, or will that only happen if I really burn the hell out of one spot?

And it's going to get (semi-gloss) painted next if that makes a difference, and I'm using a little $20 orbital sander.

[Ravant]

Well, if you're planning on wet-sanding to get a better paint application and adding multiple layers, 60's fine. If you are just going to sand 100% and then paint, go over it once with the 120.

As for the application of paint, any kind of paint that is going to have any kind of gloss to it will be very unforgiving to bumps, raises, dips and other imperfections in the wood. The light reflecting from the shadows the bumps and recesses make would be accented by the gloss. (Happens all the time if we have to bondo a car. Have to make sure it's PERFECT... or else we gotta start over, regardless of how much gloss is actually going into it.)