Prove your credentials are always current.

Annual renewal required. Working on gas without registration is a criminal offence carrying fines up to £6,000 or imprisonment. Customers increasingly verify registration online.

Building regulations compliance for electrical work in dwellings. Required for notifiable work. Without it, you can't self-certify and customers face costly building control inspections.

The wiring regulations qualification. Required by most competent person schemes. Needs renewing when a new edition is published — the 18th Edition Amendment 2 is now the current standard.

Required for oil heating installation and servicing. Annual renewal. Without registration, you cannot self-certify oil installations under building regulations.

Most clients and main contractors require proof of valid cover before you start work. Typical policies run annually. An expired policy means no site access and no new jobs.

Legally required if you employ anyone — including apprentices. Fines of £2,500 per day without it. Annual renewal, easy to overlook when you're busy on the tools.