One check Windows 7 users can do before upgrading is to count the number of .lnk files in the following two locations:
I.e. put "*.lnk" in the search box for both paths and see what it says for the total number.
On my workplace PC running Windows 8.1, total is 256 .lnk files, which closely matches the 250 Count for "Get-StartApps | measure" in PowerShell. The extra 6 are probably duplicates that get shown up as one.
As "Get-StartApps" does not work on Windows 7, the total .lnk count gives a rough idea of how many applications will be transferred with the upgrade.
On my home PC with a 6-year old Windows 7 installation, I have 723 applications between the two start menus. So looks like that would not be a good Windows 10 upgrade candidate just yet... :disagree: