WordPress MU

Hi everyone
I have an old blogging site using the Bloghoster software.
I have everything set now to install WpMu for another domain and on another server.
I will be just redircting the signup link in my old site to the signup page for the new one which I'll be using wpmu.

So I expect to have more than 15 new bloggers every day signing up to my new site.

My Q is:
Should I start with multiple databases from the start or should I wait until I reach the poing of HAVING to split database? I'm no tech person, Iam a content manager and I know a little bit of php coding. I have no mysql skills.
I prefer hireing someone to do that for me later - when I actually need it - but if its not something difficult and I can do myself at start, then please direct me on how to do it? and when? Should it be after installation is complete or befor that?

Thanks!

Well, I'd say that you should split DBs when it's needed. For example, when you get another separate physical server for MySQL or scale in some other way.

From my own expecience - a WPMU system with ~7000 blogs and ~40000 hits/day lives on 1 server, single DB (~900Mb), average server load is 0.3-0.5

Thank you VentureMaker
You're always helpful