When did I refresh my sealant?

I have 19 road bikes and an absurd amount of wheels. Keeping track of the last time I refreshed the sealant on my tubeless setups was a guessing game until I solved the issue with a silver Sharpie pen. On the non-drive side of all my tires I mark my preferred tire pressure for that wheel and if it’s tubeless, I put the date the sealant was put in. The ink can wear off so it’s good to re-mark it occasionally, and if you put new sealant in, just take the old date off with rubbing alcohol. It’s hard to calculate how much this hack will cost you, but it’s not much!