Decent is sooo context relative. If I’m in San Diego, decent takes on the subtle tones of something that matches the food I’m going to eat and the company I’m going to keep without a splashy label and splashy price tag. Usually a decent white is 15 and will be either a German riesling, NZ Suav blanc or petit Chablis.
On the red side its something that isn’t an oaky fruit bomb that I can share with friends or drink by myself. Usually sub 20 and includes lesser known Cal cab, or cru bourgeois Bordeaux or even Borgogne (cheap burgundy). Aussie Shiraz can be a good option.
In either case decent means Wednesday night wine. Something I can open on wed whether by myself or with someone and not care if I finish the bottle.
In my current local its anything I can get that doesn’t burn my tongue on the way down!