With the capturing of data by Microsoft, this can be reduced via the installation process (select advanced options and tailor as needed). Other things to keep in mind while upgrading to Windows 10 is if you have dual GPUs (for example, Intel and Nvidia), you may want to try checking in on the RTPM on both devices -- if one uses RTPM and the other doesn't, you may have trouble with the system recognizing the other device. I ran into this issue when I upgraded to Win10 last night.

Like others have mentioned though, if you don't have a strong reason for needing to upgrade, hold off until you need to.

Cheers.