Apparently, when you upgrade, your Windows 7 system is saved so you can revert if there are any problems.
However I would ask, how old is your hardware? If it is nearrly as old as Windows 7 then you may well upgrade the OS but then need a new computer at some stage anyway.
It may be as well to get a new computer with Windows 10 loaded and start anew.
I'm not an expert, but in my experience you get this problem of keeping you hardware/BIOS/Operating systems/Browsers/Programs all up to date, but also in sync with each other.
I know it's easy for me to say when it's your money but I just went through this pain about 18 months ago.
As I mentioned in another thread I still run Windows Vista on a 10 year old laptop and it works well enough for a backup l but it would drive me nuts using it everyday.