I'm computer savvy, but I'd recommend 11 months and even then ONLY if there's a real need. If you have 7 or 8 and it's working well for you, there's little or nothing in 10 of benefit. I've been testing the 10 technical preview since 10/1/14 when it first became available, and I have absolutely no use for Cortana, Edge, or any of the half-apps from the App Store. I'll keep 10 on my two test computers, but I'll also keep 7 on my main desktops and laptops. Remember that any new release is going to have more bugs than the older ones where most of the bugs have been found and fixed.
I believe, that people with less savvy, should wait 6 months to let Microsoft get some of the bugs out and more updates.
Ken -- The Computer Hobbyist
PS Last week, on my stand alone Windows 10 Preview, I selected activate and it activated to Windows 10 Pro, now I have Windows 7 Pro, 8.1 Pro and 10 Pro , that I can select on my desktop. I help people with there computers and clean them out or do complete recoveries. I use Windows 8.1 Pro, most of the time, I working to learn how to manage and setup Windows 10.

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