How will I know when my plants need to be repotted?

When you see root tips protruding from the bottom drainage holes in the planter it will be time to repot your plants.

...Another way to tell if your plants need to be transplanted into bigger pots is when they require watering more than 5 or 6 times per week - this is a sure sign that they need transplanting.

Seedling taproots can reach out through the holes in the bottom of the container well before the need to transplant.