There are many free cloud services for users to upload their personal files online (e.g. Google Drive, Mega.nz, Microsoft OneDrive, Dropbox, etc.). This allows one to free up memory in their SSD or hard drive by saving personal files them online. In that regard, you don't have to purchase an SSD that has more than 250 GB because you can save your files online for free.
Or, if you are a cloudophobe like me, you can just add an sd or micro sd card for file storage. I still keep my little 128 Gig SSD relatively happy by leaving only applications on it and storing my other working files on a 256 GB micro sd card. Copernic indexes it without hassle and I can find anything I've done in the past 6 years without having to go to archives (I'm 99.9% "paperless", meaning I have all my work and personal files handy on my device in pdf format or native format from 2009 to present--the remaining 0.1% are physical documents that need original signatures, like wills and titles).
I back up the data files every night locally to a hard drive at home. And I also back up to a hard drive at my office a couple times a day. (That hard drive stays locked in a cabinet). A third back up drive sits in my briefcase, too. Just backing up data files with something like MS Synctoy only takes about a minute if you do it regularly.
But go with the cloud if you aren't hyper-OCD nervous about 3rd party access.