My last remaining Windows machine, which is used for photo and video editing in bursts during certain times of the year (I'm an amateur photographer/videographer with seasonal subjects) a self-built i7-3770k machine, was updated following every editing session until recently. I'd finish what I was doing, allow Windows 7 to apply any needed updates, and then shut the machine off until it was needed again. The machine is now running a Windows Insider Build of Windows 10, because I needed to know if several somewhat esoteric and out-of-date applications for my other hobby, ham radio, were going to run properly. I keep good backups, however; this includes a full backup of all my photos to Amazon.
My Apple devices are updated as soon as Apple releases an update, with two exceptions. My MacBook Pro, iPad, backup iPhone (usually used for timelapse video now) and AppleTVs are updated immediately when an iOS or Mac OS X update is available. I also update my AirPort Extremes on the same policy. Exception one is that my current phone is updated a few hours later, once I notice no major issues with the iPad and old iPhone. Sometimes I wait a day or two if I know I'm going to need my phone no matter what. Exception two is that I'm currently running beta iOS 9 on my old phone, because I felt adventurous.
None of my machines or devices are used for production work I'm paid for, my employer handles maintenance of my single-device work computer, so I can afford to take the updates regularly.