30,000 wind turbines around the world have already entered  the second half of their 20-25-year design life, already having long since fallen out of standard manufacturer warranties. The turbines now increasingly attracting the attention of O&M technicians are bigger, heavier, taller and much more complex than their predecessors. The rise in installations from 2010 was accompanied by significant shifts upwards in nameplate capacity, tower heights, rotor-blade lengths and operating reliability. This enabled wind development at sites previously considered economically unviable on the grounds of, among other things, low wind speeds and extreme temperatures, remote and hard-to-access locations, hilly and forested terrains. The O&M sector’s challenges will grow alongside the expansion in the number of turbines it services, and their technical demands. The next generation of Multi MW onshore machines, with rotor diameters of at least 150 meters, mounted on 160-metre towers, pose a number of questions for future maintenance regimes. The cost and availability of cranes with sufficient lift and height capacity to replace, say, a gearbox, is a key priority for operators.