how to inspect distributor cap

I want to inspect my distributor cap and rotor on my 99 astro van. What should I look for that would indicate it is bad or worn. I can't afford to buy a bunch of parts but everyone says to replace spark plugs and cap if its is running poorly.

p.s. what kind of plugs should i get?

Use the OEM AC-Delco plugs that the parts book calls for.
The cap and rotor the best thing is to take it off and look at it.
Check for moisture or cracks or corrision. Look at the end and base of rotor for carbon tracking and wear. Check the dist shaft for side play.
You did not say how many miles or what engine.
Plug wires is another main idem to check along with fuel and air filters.
And have a look at belts and hoses to. Check for lose of coolant and remember the coolant needs flushed and changed ever so often.
MT

If you do determine the cap and rotor are bad, get an AC/Delco replacement cap and rotor and not ANY of the aftermarket ones, they don't work as well as the AC/Delco units. I second the AC/Delco plugs as well, they are inexpensive and you don't need any of the fancy quaduple electrode plugs, etc...

I once put on an Autozone- (RED) cap and 1 week later wife is stuck in town- won't start- towed it home- put the old A/C delco cap back on- it started-- put a new A/C Delco cap on- it ran fine-- never could see a differnce in the two caps- other than the color-- I ran over the Red cap to vent my frustrations.......