Checking the size of the session cookie

[eluser]Daniel H[/eluser]
Hi -

Does anyone know how to check the size of the session's user_data? I'm having a few problems whereby the session data is being lost occasionally without any obvious reason, and I guess one potential issue is that it is exceeding 4kb. I'd rather not switch to db sessions just because I think that's overkill for my needs.

Any ideas?

Dan.