There will still be some value in a 2014 Avensis Estate - look here for a valuation: www.honestjohn.co.uk/how-much-is-my-car-worth/. Whether to change it now depends on your requirements - 10,000 miles isn't a huge amount but, if they're mainly on the motorway, a diesel might make sense. Diesels are also better if you need to tow. If you decide it is time to look for a new car, a hybrid or plug-in hybrid might work for you. Plug-in hybrids work best if most of your journeys are short (below 30 miles, for example) and you can charge at home. A standard hybrid isn't as suited to motorway driving as a diesel, but should be economical day-to-day. Don't dismiss a new petrol car, either, they're generally very efficient now.