Fuel economy. Obviously, a miserly bike has a small engine capacity. Two-strokes are very cheap to run, but smelly and polluting. Read this guide to improving economy.
Luggage makes a bike more practical, but it needs to be removable or it will weigh down the bike and impact on fuel economy.
Tyres. You can sometimes pay more for a set of two motorcycle tyres than four car tyres. It’s due to economies of scale. Look for a bike with regular tyre sizes, nothing too bizarre such as a 240mm rear tyre!
Bike brands. Japanese bikes have always been known for being reliable, but most bikes these days are pretty reliable. Get something basic without electronic extras that can fail and be expensive to repair. Check out the most reliable bikes.
Service intervals. Dirt bikes might be cheap, but they have frequent service intervals. Modern road bikes have long service intervals. However, be aware of any requirement for expensive oils.
DIY. Buy a bike that is easy to service yourself. Hi-tech bikes require computer fault finding, but you can still do your own oil change and filter clean.
Parts cost and availability. Ask about prices for common parts and their availability. Some parts can be very expensive and the dealer may have to order from the importer who may have to order from overseas! Read about the scandal here.
Fairings. Avoid bikes with fairings. Mechanics charge by the hour and removing and replacing a fairing adds to the time and therefore your bill.