Recently, we've had a new ticket to order more SSDs for replacement in older model databases. https://rt.wikimedia.org/Ticket/Display.html?id=9455
We'll need to gather our current database servers and warranty expiration dates, we can also then break them up into service groups and have Jaime or Sean give us some insight into which are nearing the end of life for their service, and which are worth retaining and replacing bad SSDs and other parts.
Once we know how many of these systems we plan to continue using long term, we can better estimate how many SSDs to keep on hand for replacements.