Not as easy as you think. I tried to upload W10 when it first came out, The microsoft system checked that my pc had all the right hardware. It did. It was uploaded and would not work. It had a fatal error. This was not uncommon. No-one could find out what the error was and there was no way of remedying it, so W10 had to be uninstalled and W7 reinstall ed
A month ago my pc fixer recommended updating to W10. He came round to do it, but (again) it wouldn't load. In the end he had to take it away to his magic lab in his back bedroom and work on it, He did it in the end, but advised me to consider buying a new pc. This one is 8 years old and worked fine until W10 came along.
I have had it loaded onto my 1 year old laptop and it runs and uodates without problem . DH has had it loaded onto an identical laptop and it works fine but will not update. Instead the machine loads the updates, discovers they cannot be installed and unloads them again. This takes anything from 2 to 4 hours, during which time the computer cannot be used.
By all means move to W10, just do not suppose it will be a doddle - It might be - but on the other hand..........