Is it worth attending festivals?

I was wondering if anyone works at - big day out, splender in the grass etc etc, is it worth it? Please all info would greatly appreicated.. dont want to waste my time trying to get in if its not viable $$$ wise. Thanks

I've made some of my best money at big local festivals.

I usually make a months rent in a weekend at carnivals and festivals. Then there are times when I don't even make enough to cover my booth fees. It's a gamble. My advice, yes, do it.