Asking as I've got a lot of spare components lying around that I'm planning on turning into a NAS. If it doesn't work out I'll buy a pre-built enclosure and reuse the drives.
Definitely try re-using what you have already. Just keep in mind that a NAS usually runs 24/7 and old gaming PC parts are usually quite power hungry, so it might cost a lot in terms of electricity.
Yeah this is definitely a downside to using spare gear over purposeful purchases. I think it makes sense to use what I have and optimise later. I've got an old intel i5 and mobo I'm planning on using for the NAS. Need to find another use for my old Ryzen 5 2600X.
I was going to say this too. It's fun to have a project to do and to recycle old parts but something custom built for being a NAS will most likely be less power hungry and be less effort to maintain.