I tend to take a yearly vacation, but I think I would get nowhere near enough frequent flyer miles to redeem anything worthwhile. What is the minimum frequency of travel that you would recommend?
I think it's worth signing up for mileage points anyhow as you can trade them with other people on other sites and also it entitle you extra luggage allowances on some airlines. Don't forget many have partner airlines and loyalty schemes as well, so you could use them for other programs like hotels. Many of the Hiltons and chain hotels have partnerships with airline programs or car rental companies.