Hi, think that it was asked before and it was 45 days but didn't find the post.
How many days in advance can I renew my one year extension for Thai child care visa ?
TLDR : Answer Summary
The renewal for a one-year extension of a Thai child care visa can be done up to 45 days in advance at certain immigration offices like those in Chiang Mai and Bangkok. Other offices may only allow renewals 30 days prior to the expiration date, so it's advisable to check with your local immigration office for specific rules.