Models, where, when and why?

Joins could get complicated pretty quickly in my experience, so in my personal opinion I find it a lot easier to write simple queries

Yes, I used to do that too, but I very cordially advise you to take the plunge and learn proper SQL. At some point, you're bound to run into performance problems, plus it puts you in a poor light professionally.

I have a book (well, in PDF format) called "Simply SQL" by Rudy Limeback. I find it very useful. Rudy has more than 20 years experience working with SQL and he actually hangs out at the Sitepoint Forums, where he is very helpful.