I favor indefinite changes. To deal with the problem of the possible troublemaker changing their words, it's not beyond reach to hit the "quote" button and preserve a post in the very next post. If someone is going to make trouble, they're going to do it more than once, so missing the first time may not matter. I favor letting the deviant go a few times rather than holding everyone to a time limit.

People with Parkinson's (PWPs) have a similar problem to others, in that if someone goes "off"--meds/chemical costume not working---unpredictably, it might take hours or (sadly) days before a person can type or manage the buttons again.

The simple expedient of typing on another "page" such as a word processing program and then pasting the item to the reply screen is beyond what many a PWP can contemplate and/or fuss with.

Jaye