It's not something you choose out of the ether and wholly depends on how the substrate is constituted and how fast the plant is drinking it down per day.
1) water entirety - don't half water or spritz the top. These are bad habits. If in soil minimal runoff is goal as to not waste your amendments. In soilless you religiously get 10% runoff waste water (err on high side if any). Waste water is fine for any plant in the earth, but not potted plants. toss down the drain, otherwise, and don't let the pot sit in its piss, regardless of soil or soilless.
2) wait for appropriate dryback. In soil / high water capacity context wait for 1/2 to 1" deep to dry on top, then repeat step 1. In something like coco coir that holds a lot less water per volume, the trigger is around the time the color changes on top. Learn the weight difference and that's the best way. In hindsight you can easily predict how much water you need to use as far as not wasting fertilizer or having stagnant water lying around. Water at same loss of weight and it requires same volume of water.
If you want to do more frequent fertigations after a healthy plant mass has formed, you still need a properly constituted medium and some minimum dryback to maintain healthy rootzone. In high capacity water medium, you want 50% perlite or similar. In coco coir, 33% is fine. Being off by a few percent is irrelevant, but shoot for these numbers and it's virtually impossible to overwater. It gives a 1:1 gas:water misture in the substrate.