Just to be anal-retentive, your SSD card is storage (remains viable even if your computer loses its pulse), not memory (suffers brain death within moments of cardiac/motivated electron interruption).

Now for actual contributory content, because my wife and I occasionally work on projects "together", we treat each job as a separate catalog. Once the job is done, we copy the job to external HD storage hanging off our Time Capsule, delete the folder off our internal HD, and create a new catalog for the next job. Since we usually edit the job within days of the shoot, we don't bother with LR Catalog backups, as it's kept as a backup via Time Machine on a different drive and then cloned to alternate external HDs as part of our off-site backup routine. I made it a long time on a 160GB internal HD on my MacBook Pro that way.