Is It Still a Good Idea to Use a Separate Drive for Your OS?

I'm building a completely new PC after years of upgrades to my old setup, which features an i7-6700k CPU and a GeForce 2070. I have a few HDDs and a DVD reader/writer, but now I'm looking to modernize. I already have all my parts on order, and I'm considering whether to invest in a smaller SSD to dedicate solely to the OS. Previously, I kept Windows 10 on a small SSD to avoid overloading it, but I'm wondering if that practice is still advisable. Should I take the time to scavenge a 1TB WD M.2 from my old PC, or is there a better solution? Any thoughts on storage setups or tips for my new build would be greatly appreciated!