I don't see how it could harrm the server and besides there are threads that are over 65k on FR.
The mods will come in and let us know when we need to start a new thread.
I don't know the reasons for it. John Robinson tried to explain it to me once, but I don't speak tech.
The folks on the Natalee Holloway threads, and other long-running daily threads got in the habit of starting new threads when the approached 25,000.
If you don't want to do it for some reason, and don't believe that it hurts FR server response or don't care, that's your personal decision, although I don't know why you'd feel that way.
Do as you wish. If the entire thread disappears one day, you'll know why.
That's all I'm saying.