What is the time limit between stretches?

I just stretched to a 8g yesterday and I had no pain? If I had to say I had pain it would be little to no pain. I just stretched to a 10g on March 31st after having 12g plugs in since January. I truly think I could have started off at a 10g because the 12g was very loose in my ears initially.

My goal is 2g-0g so I want to know what is safe time to stretch between these sizes as they aren’t extremely big but big for a beginner so I should be careful. I do plan to be cautious moving forward, I just want to start wearing tunnels soon.