abs light not showing up when key is switched on?
 

I have a 99 dodge I need title rebuilt which means a state inspector must come and check it out, which one of the things he's going to check is if the abs and air bag light comes on for3 to 5 sec what's wrong if it doesn't come on?

Could just be a bulb burnt out. It isn't too tricky to pull the gauge cluster out and access the bulbs. Swap the ABS bulb out with a known good bulb (signal, hi beam indicator, etc) reinstall and try again. You may be able to visually inspect the bulb for a burnt element as well.

How often do they go out

im not sure about a '99 cluster, but my '01 uses bulbs just for the back lighting and turn indicators, all of the warning lamps are backlit by non serviceable LED's, first i would check all fuses for the ABS and airbag and go from there