So here is the current setup:

MacBook Pro connected via TB4 to:

OWC Thunderbay 4-drive RAID in RAID 5 - this holds 8 TB of photos (mix of personal and landscapes that I do sell) as well as backups of important files on the internal MacBook and external SSD.

24 TB total; 13.4 TB free

4x8 TB Seagate drives (ST8000NM0055) bought in 2021 [edit - corrected date bought] with 31,000 hours use

OWC is backed up to:

Synology NAS DS918+ in SHR-1 purchased 2019

32 TB total with 8 TB free

4x12 TB HGST drives (HUH721212ALE600) bought in 2019 with 53,000 hours use

Important data from OWC and all movies backed up to two 18 TB drives connected via USB in single 2-bay enclosure  

One has 9.6 of 16.6 TB used

Other has 9.2 of 16.7 TB used

The MacBook and OWC are also backed up online via BackBlaze so photos are in 3 spots in house and 1 online

———

Any concerns with drive use time?  Age??

Do I gradually replace each Synology drive with a 16 TB one at cost of $350 each and allow each to rebuild?

I’m a bit worried about the amount of ‘stress’ that may put on these 6 year old drives

Is there any benefit in spending the same amount ($350) on each of four 4TB Samsung SSDs to use with the new OWC 4M2 that would connect to the MacBook as ‘fresh’ and faster drives?

Edit: for the OWC 4M2, would appreciate any recs on 4 or 8 TB drives that are best bang for buck for storage in RAID5