Yeah I'm doing something similar. The hours I work varies, this week I'm waiting for a client to get back to me about some stuff so it'll be < 20 hours, but I never work more than 40. As you say I could probably do this until I die. I don't have a family yet though, I'm sure things will be different then.

I'm also travelling in SE Asia so my outgoings are very low. I didn't realise how cheap it was here. I'm bringing in nearly 5x (before tax) of what I'm spending.