Always read the safety instructions, replace failed bulbs to avoid overheating, and switch lights off when going to bed or going out.
Use energy-saving LED bulbs, which emit less heat and cost less to use, make sure lights are connected via a 30mA RCD protected socket, or consider using battery-operated lights to avoid having trailing wires.
Touch the wires every so often to check they’re not overheating, and be careful with wires and electricity near any sort of water – take care when watering the trees. Visit RoSPA at rospa.com for more information.
Check that lights conform to British Standard (BS EN 60598). See gov.uk for more information.