All depends ,my experience mild chilies ripen faster than the hotter ones.i would say a month to a month +..weather also plays a factor....I would let them stay on the plant ripe as they build heat and flavor..just don't let them start to wrinkle unless u plan on drying them..example a green habenaro will taste like a bell pepper and a ripe one burn your tongue off.

And then there's jalapenos that can take so long to color that people don't bother to wait...

My Congo Reds take a about month to turn color after reaching full size. Once they've decided to get red, then I wait another 2-3 weeks before picking. It's true, the longer they stay on the tree the hotter they become.

Although the Congos are on average only 50-70% the heat of Bhuts, a few clearly exceed that average when left on the branch longer.

Patience is a virtue in chile growing