I’m using an old laptop(5+ years), and my HDD was taking too long to boot, between 40 seconds and 1 minute, then I bought a SSD, opened the laptop and replaced the HDD(just remove and plug the SSD), here are the results:
systemd-analyze Startup finished in 1.148s (kernel) + 1.953s (userspace) = 3.102s graphical.target reached after 1.931s in userspace
3 seconds to boot, I’m using KDE now but I bet other DEs and distros have similar results, so between pushing the button to turn on the computer + login it takes about 10 seconds, that’s amazing.
It’s not just boot time, apps launch in 1 second or 2, a bit more heavy apps like LibreOffice launch in 3 seconds, it’s just fantastic, games boot faster too.
I highly recommend everyone buying a SSD, if you don’t use a lot of storage it can be a cheap upgrade and everything seems faster(buying more RAM or faster RAM helps too), just get a 120 or 240 GB SSD, install any distro with a pendrive and you are good to go. An alternative is putting all your system in a SSD and your files(/home) in a HDD because HDDs are cheaper, that might work well too.