I have 5 sites but they are all free hosting like blogspot and wordpress I have a good content and a visitor I just don't have money to invest for the domain and hosting.
Up until recently I had about 8 (I was only actively maintaining 2 or 3 though). I just did some house cleaning and now I'm down to: 1). My main business site - gets nearly all my time 2). My personal portfolio - not necessary to update frequently 3). Small hobby site - update this one once every month or so 4). Another small hobby site - update it just a couple times a year
As I write this I have more than 200 websites and they are a big problem to keep up-to-date even with WordPress and the plug-ins. However, most of them make regular profits even if it is only a few pound a week, but it all adds up and they are worth keeping. Every now and then one of them gets hacked and luckily I have backups of the design and restore files so I can replace them fairly quickly. Out of all of the sites which I have Pareto's rule applies and 80% of my income is generated from less than 20% of my sites, in fact to be perfectly truthful it would be from 5% of sites. This is always the way you either go for the shotgun approach or you have to watch your websites very carefully and make them grow.. I hope this helps? Kind regards Kevin