How many DAYS does it take for signs of over/underwatering to occur????

As the title implies, I'm simply interested in understanding how long it takes for the symptoms to occur. Most people aren't sure whether their plant is showing signs of over or underwatering, how long does it take after watering for these signs to show?

My plants are getting droopy and kind of shriveling, but not in a limp lifeless way, they actually do look like they are full of water, and the soil is slightly moist still at about the 1 1/2inch mark. They're only seedlings, started on a Sunday this is week 3 and they are 3rd/4th set of leaves (although 2nd isn't nearly as large as first yet). I have no pictures because my Iphone refuses to email. Saw some symptoms yesterday and they look worse today. BUT-

If its overwatering then they will eventually start to get better and I need to wait for them to recover. watering now would surely kill them. It's been nearly a week since I last watered. . . medium is Botanicare Aeration formula (guy at the shop recommended it) and its, get this, supposed to DRY FAST

In my experience, under watering will make them straight up droopy. Over watering will make them droopy and rolling inward or kinda like curling. Thats just my two cents. Good luck and good growing

they definitely look like they are rolling inward. . . what the fuck? It's been like a whole week already; factoring in recovery time from now, does it sound normal to water seedlings once every 9-10 days?

On a side note, I have red dixie cups, and I poked 4 holes nearly the size of a pencil in each. Is that not enough for drainage?

I don't know why it would need to dry fast. From my experience when it is under watered the leaves seem like there going to crumble instead of that firmness from a good leaf. Over water turns the leaf rock fucking hard. They are seedlings it might be a humidity issue or heat issue. The stamata might be trying to transpire more then they should. What is the temp and humidty level.