It shouldn't take too much time tbh. There are several red flags that you can spot pretty quickly like the team behind the project (are they legit or just made up profiles?), volume (is it getting PnD frequently or not?), whitepaper (is it a legit whitepaper or just another copy-paste from another project?), also the community, etc.

I don't hold any worthles vaporware, but if I did because I made a bad choice in the past and fell for the FOMO buying wave, then I would probably wait for another altcoin cycle before dumping every single shitcoin.