Giselbaer's Durability Viewer

Mods
653,676 Downloads Last Updated: Apr 23, 2019 Game Version: 1.12.2

Durability Viewer standard display

Durability Viewer showing your free inventory slots (31), slightly damaged bow and helmet (negative, what's missing to 100%), more damaged pick and chestplate (positive, remaining durability), arrow count (59), and undamaged pants/boots.

Armor around Hotbar mode

In this mode, the armor is shown around the hotbar, and the "percent to show damage" option is set to 100% so you'll always see remaining durability instead of item damage taken. (These options can be set independent of each other).