1h    May 16, 21:03:48     Word in the... underground.. is that ErnaHappyMomsDay is now residing 6 feet underground wearing some pretty fine jewelry.
6h    May 16, 21:03:40     ClementThankAVet left behind some protection in Downtown, Los Angeles.
4d    May 16, 21:03:38     Word on the street is that 233 BGs are hiding in Los Angeles.
6h    May 16, 21:03:36     Word on the street is that joraz has fallen out of favor in Manhattan, New York.
1h    May 16, 21:03:34     Word on the street is that Seattle is paying top dollar for Marijuana and Philadelphia has cheap Marijuana.
1h    May 16, 21:03:31     Word on the street is that New York is paying top dollar for Grain Alcohol and New York has cheap Heroin.
1h    May 16, 21:03:29     Word on the street is that Las Vegas is paying top dollar for Amphetamines and Las Vegas has cheap Cocaine.
1h    May 16, 21:03:27     Word on the street is that 139 are locked up in Las Vegas.
N/A    May 14, 20:04:15     You witnessed ebausestcv WACK MikeLipkind

i think 2-4h for the graverobbing tips would be plenty of time as i only tip for those with an open timer

Reasons being:

The graverob tip is usually used instantly and not something you bulk do for the rest of the day, even if you do after an hour the grave usually would have been disturbed already.

6 hours for specific the BG tip, I think 4 hours is fair to try again at the BG if you missed/wounded/injured first time and adding 2 hours sounds like enough in case one went offline or something and came late for the shot.

4 hours for the BG city tip, that's usually changed after less than 4 hours so after 4 hours, mostly the bgs in that city would be cleaned with enough people hitting them as we usually see.

Since all top 3 drugs prices change after an hour, keeping the tip for an hour is already too long.

The jail tip, if there's less than an hour I'd vote less.

The witness statements, for the wacks I think we can keep them forever.

For the pickpockets since they can't be sold to warden, it's useless to keep. So 2 hours for them is enough before deleting.