My insurance PL/EL is £300 a year. So of my £30,000 turnover, my expenses should be £1,500 so that leaves £1,200. Road tax £225. £975 left. A bag of resin £75. A van service £300. We're now down to £600. Mobile phone say £20 a month - £480. Home office £15 a month £300 left. Ooohh, van insurance £350. Wait, hold on we haven't got a van, say £5,000 over say 5 years, no fuel at perhaps £100 a month. As you can see, 5% is totally inadequate.