You've NEVER lost anything??? Never got in hurry, got pressured, got pulled off a job in the middle to handle an "emergency", got phone calls / questions that distract you?.....Without EVER loosing anything, then you are really good!
I know I have lost a couple of individual tools here and there over the years. Nothing big / high value. #2Phillips screwdriver, 9/16 wrench, the occasional allen wrench used for an adjustment.
I have also found some stuff left behind - usually assorted wrenches and such...kinda the same as what I've lost. Most expensive finds where a brand new SO ratchet under the hood of truck (who knows who left it there) and a DA sander left by mfr's paint shop in a brand new machine (UPS'ed that back since I know the paint shop mgr).
Now, borrowing and then loosing someones else's tools is different - I have never done that. Period.
nothing of extreme value. i think in the last couple of years i've lost a 5/32nd allen wrench which we keep by the tote full of all sizes.
and it was only lost because it fell out of the holder because of how loose they got in it.
but losing a wrench, or a socket....? no, i always pick up and clean my tools as i put them back so its easy to know if i left something behind.
i'm not perfect by any means, i've left things behind after getting called to another job somewhere, left locks on machines by accident after getting called out, and then realize after picking up from that job that i left something at the last one and have to cart everything back over and pick up again.
but if i have to borrow someone else's too. i make sure that its the first thing i pick up and clean, and it goes back on their box or in their drawer before any of mine get cleaned. respect someones property more than you respect yours and you won't have a problem borrowing or loaning tools to those people.