For lipsticks and pencil liners, if there's no bad smell, and you keep them capped they should last you until you finish using them up. When in doubt, dip in alcohol.
For e/s and other powders, those should last you a lifetime so long as you keep the lids closed.
Liquid liners, I'd be a bit more wary as every time you use them you expose the applicator to air and its particles and then dip it back into the liquidy goop. Generally the lifetime of these is about the same as mascaras (~6 months). Granted, I've kept some of mine for much longer and still use them, but to each their own risk as I'm thoroughly aware of mine. However, you said purging, and if this is stuff you're considering to sell, then if it's older than 6 months I wouldn't sell it. (And in general, if you've personally used the liquid liners without a new and clean applicator, I wouldn't suggest selling it to others. What may be natural flora for you may be harmful to someone else.)