Actually, a few years back (2018 I think?) I had to replace a water heater in one of my properties. Cost including installation was around $800. I just expensed it and considered it done. So far, so good.
My reasoning was that besides being less than $2,500, the new water heater replaced the old, broken water heater and basically didn't really add value to anything. It just "retained" the value of the property. So I saw no reason to capitalize/depreciate it since the cost was under the threshold. My nieghbor (A CPA) at the time did indicate it was a grey area, and that any chance of that being questioned was closer to none, than it was to slim. I agree.
Besides, listing it as a separate asset could potentially subject me to the county assessing a yearly tangible property tax on it. I know for a fact they do that with short term rentals in my county, since they are required to be "registered" at the county/city level.
