How long does it take for the fit of a new JB to work itself out?

I placed an order for a Jailbird from Mature Metal just over a week back. This marks my first time purchasing a brand new custom steel device, and naturally I’m keen to see if I managed to get the specs right…though I suspect at least one adjustment will be needed after it arrives. So… How long did you all take to realize your specifications were correct (or resolve any issues)? If you ended up needing a smaller ring size, how long did that realization take? I’m simply curious about the timeline before people could confidently say “aha, now I know my true measurements”. Any input is welcome.

First off, congratulations on switching to a custom stainless steel device. It took me quite some time to make the jump from plastic, but I haven't regretted it at all. Lucky for me—and thanks to MM's advice—I got the cage diameter right immediately since that dimension can't be altered later. My gap measurement was also good, though that is easily changed if needed. As for the base ring size, well, a few months passed before I found what felt comfortable yet secure. I eventually went down one size on the base ring. A year later, I tried dropping another size but ran into issues after wearing it for several days. You often find yourself wondering, "it feels so good, but could it be even better?". Following advice from several members here, I sent my cage in last year to have half an inch removed from the length. It improved both comfort and convenience—specifically because I sit right at the end of the cage now, keeping me aligned for urination most of the time. I can use a urinal without worrying about making a mess.

Generally, you should wear the device for at least 48 hours before making any sizing decisions. The base ring is an exception; if it chafes raw, take it off and don't bother trying lube to fix it. Send it back to MM and ask them to adjust it to a larger size—it's not costly. However, if your ball escapes through the bottom, you need a smaller ring. If you think the cage itself is wrong in size, wear it for at least one or two months before deciding what to do next. When I received my shorter cage, it felt off for about a month until my body learned to accept it. Remember, aside from the base ring, your body needs time to get used to a new cage.

Thank you both! Very helpful information and much appreciated!

I agree with Tame Lion. Once you get used to the cage, it's great fun being locked inside steel!