@nineth9t There is no hard limit on the size of toots, most mastodon instances stay with the default 500 characters maximum which is the lead developer's idea of an ideal size (mostly for screen layout purposes as he once explained in a response against loosening that limit).

Pleroma instances usually have larger limits. I have various accounts and limits varying from 500 (argh) to 65,535 here. Some Hubzilla systems allow 200,000 chars too.

And all of those work, nothing breaks if someone posts a bit longer. Sadly, they make it hard and inconvenient to change in Mastodon -- to try and keep the 500 in place.