Reimbursement for cancelled job

Hey all, I’ve been in independent pet care for almost six years now and this happens quite regularly and I’m wondering how you all handle it.

I’ll set up a pet sitting job with a client, they’ll give me the dates they need me and I’ll put them on my schedule. In between then and the job I’ll get many other requests for house sitting that I’ll have to turn down. Then a week before their trip they’ll cancel on me. So not only am I out of the money I’d make from that job, I’m out of the money on all the jobs I had to turn down because of it.

Just wondering some ways you all have navigated this. Have you set up a contract? Is there a specific name for what this is?

Thanks all, the consensus seems to be half the deposit upfront