If you are looking for last-minute Christmas gifts and don’t know what to buy, gadgets and accessories mean you don’t need to know someone’s clothes size or availability for a night at the theatre.

There’s no need to buy the latest shiny new phone or smartwatch – there are some smaller things that will be welcome presents and help extend the life of your loved ones’ existing electronics.

Phone cases

The most sustainable tech is what you already have, so cases and accessories to keep it in good nick are a good buy. As long as you know the model of the phone, finding a case is easy, with hundreds of options costing from about £10 from longstanding third-party accessory brands such as OtterBox, Speck and Spigen. Apple, Google, Samsung and others make their own cases.

If you want something more sustainable, a couple of brands make cases from biodegradable materials, costing from about £25, including the Canadian company Pela and the British outfit Wave. Wave will even accept old cases back for industrial composting – send one and you will get 20% off another case.

Phone cases can also replace the traditional Christmas wallet purchase, with models featuring slots for credit cards, either in a flap over the screen or in sleeves on the back. There are many options, starting from about £10. Luxury versions such as Bellroy’s leather phone case cost £39 and up.

Most cases don’t cover the screen directly, which is where screen protectors come in. They are available in a variety of different materials, including cheap plastic ones, hardened glass ones and even liquid ones. They can be bought from phone shops, manufacturers or from big case makers, and cost from about £10-£15 each. Wave has a recycled glass version for £15.

PopSockets and grips

A phone grip could be the cheap gamechanging accessory to help prevent smashed screens. There are many different types to choose from. Phone rings, such as the popular Spigen Style Ring (about £13), stick on to the back of a phone and have a flip-out ring to put a finger through. Phone loops come in a variety of types, including straps and fabric bands. The most simple act like a rubber band that fits under a phone case and over fingers; others stick to the back of the phone. They cost from about £5.

One of the most popular grips is the PopSocket, which is like a pop-out handle you stick on the back of your phone. Original PopSockets cost about £11, or you can pay more for one of a wide range of designs, including ones for fans of Pokémon, Harry Potter and Star Wars.

Watch bands

Smartwatches haven’t changed much in the last few years, so instead of buying a whole new one, choose a replacement strap to give an existing one a fresh new look. Each of the watch manufacturers sell a plethora of their own straps and bands, including Apple, Garmin, Google and Samsung. They cost from about £45.

Many third-party accessory makers also sell cheaper straps for the most popular watches that use special connectors, such as the Apple Watch and Pixel Watch. Other smartwatches including Garmins and Samsungs can usually accept standard straps with pins. Straps are available online and from most high street jewellers; just make sure you buy the right width of strap for the lugs of the watch.

Batteries and chargers

One of the things to wear out first on modern gadgets is the battery. A replacement battery may be the best option but backup power packs can help keep phones and other USB devices running through the day. They come in a variety of different colours, shapes, sizes and capabilities, with some powerful enough to charge laptops alongside phones, tablets and other smaller gadgets.

Good small ones with enough power for an 80% phone charge cost about £16 and are the size of a chocolate bar. More innovative ones, such as the Anker MagGo range (£26 and up) can wirelessly charge your phone on the go, sticking to the back of MagSafe compatible devices, including iPhones or Android with adaptors.

Refurbished headphones

Wireless earbuds and headphones are some of the best gadgets out there but they aren’t the most sustainable products as they often have unrepairable designs or difficult-to-replace batteries. Buying refurbished models helps the cost and the planet. Excellent options such as Sony’s WF-C500 earbuds are available for about £50 from places such as Back Market.

Apple’s popular AirPods 3 cost £149 refurbished straight from the manufacturer, while the excellent QuietComfort Earbuds II cost £190 refurbished direct from Bose. Both come with all the accessories you would get if buying new.

Refurbished noise-cancelling headphones also make great gifts for those who want a bit of piece and quiet. Sennheiser’s tremendous Momentum 4 headphones cost £194 refurbished by the manufacturer, while Bose offers its commuter favourite QuietComfort 45s refurbished for £189.95. Third-party retailers such as Back Market have other options available from brands such as Apple’s Beats and Sony.