How long is too long to talk to a potential date?

Depends on the bonding. In Today's world it is only good to keep in touch with as many. Meeting has become so difficult especially if long distance. But if one is nearby and avoids meeting, then there are other issues that have not yet surfaced. So it's better to disconnect.

A few days to a month but after 30 days if you are not ready to meet me it is honestly clear you never will and it is a waste of time

It depends. I don't know how anyone would set a time that is "long enough" before meeting. How far apart do you live? Is the other person waiting on a divorce to be final before really committing? Do they both work everyday jobs and getting away is hard or impossible because you have not been on that job long enough. Was there trouble talking and you broke up and then got back together and the second time its taking longer to regain trust again?.

Anything more than 10 messages each is a waste of time

I never done dating sites .
I knew a fella and he went on one of those dating sites and he ended up mental over the person he was supposed to meet

As long a it takes to establish trust. You you don't feel it, then don't rush it.

2 weeks max unless there’s extenuating circumstances.

As long as you have something meaningful to talk about

How about until you are tired of talking?

2 weeks to a month

5-10 mins mostly

1 month