Hi I'm looking for a decent pressure washer proberbly petrol driven for cleaning drives and patios etc, not for every day use may be 2/3 times a week, anyone know what I would at least need in psi? Seen a few 3000psi on amazon etc for around £300 new, also dose anyone know the life expectancy of one of these machines? I don't want one that's going to be knackered after say 30 jobs.