Different accounts per domain?

I have been reading this forum for about a week or two now, and I have become very interested in starting a website to test and learn SEO from.

My question is, I have seen many things that you do not want to link multiple domains to the same account (hosting, adsense, etc).

Is this true? You shouldnt have more than one domain on your hosting plan, adsense account, or anything else? It seems like that would cost a lot of money to maintain.

Never heard of that. I run three different sites off one host, and I'm pretty sure you're not allowed more than one Adsense account per I.P.

I would follow the terms of agreement/service or whatever of the company you're using to monetize your traffic with and follow that.... You might not be supposed to use multiple accounts, and I certainly dont think it has benefits besides rare situations.