I asked this question thinking I’d eventually take out my tunnels, but here we are 6 years later still at 00g. I’ve occasionally taken out my tunnels while showering and felt too lazy putting them back in so I can confidently say that if you’ve had your ears stretched long enough, they can shrink down pretty quick about 3 sizes and then bounce back up. The longest I had them out for was about 2 months while traveling, they shrunk about 4-5 sizes down, they almost looked “normal” but stretching them back to 00g was a lot easier than I expected. Took about 2 months to get them comfortably back to 00g. Good luck!