Help me find a word for an estimate

[HappyGoDucky]

Hello,

New business so new to quotations/estimates. I'm looking for a word/sentence to cover possible breakages. For example job requires heavy use of a specific tool, its quite possible one will do it but also just as likely a part (think blade) will suffer breakage. How do we word the potential charge?

TIA

Thank you everyone for your kind replies. Taking it all on board. I will look into adjusting hourly rate I think.

Check out tool hire charges.

Diamond cutting blades for example. the hire agreement assumes a maximum mm of use per hire. There is a charge for replacement blades.