How do I tell how much durability is left on my DIY tools?
There isn't a really good well to tell the state of tools in-game. As of right now I'm using Flimsy Tools, and its often a pain to tell how much durability is left within my tools, so much so that I'm constantly bringing 2 of each tool just to avoid constantly needing to recraft tools in Tom's workbench.
Add to that, the only "real" time you can tell the durability of your tool is when it hits 0 and your villager sings a sad song for it.
How do I tell how much durability is left on my DIY tools?
Sorry but there is no known visual indicator of this.