Hi Christen,
If you are tracking appliance replacements, I’d recommend that you record the appliance type, appliance model, serial number, warranty, supplier and invoice info, warranty claims, pictures, notes about conditions, major repairs, etc. As you can tell, it’s tricky keeping all of this information up-to-date since it involves the initial purchase and any notable events.
My recommendation is to use a property maintenance software platform that allows you to track all of this information when you purchase, inspect or process work orders on your appliances. Just be aware that most systems let you track items purchased, but they don't help you with the rest of the process. As Matt mentioned, you can add notes into your property management system, but your staff will get better and more timely information if they use a software platform that records this information as a part of the purchasing, inspection and work order process.