It's a completely reasonable question. It's also one that shouldn't need a phone call every single time.

Customers asking what time you'll arrive isn't unreasonable - they've got a day to plan around, a dog to put away, a parking space to keep free. The problem isn't the question. It's that answering it usually means a phone call, mid-job, to someone who doesn't actually know either.

Why this keeps happening

Without a shared, customer-visible schedule, the only way to find out timing is to ask a human directly, who then has to check with another human, who might be up a ladder at the time.

Giving customers the answer before they ask

A secure schedule link, sent automatically, lets a customer see when they're booked in without needing to call anyone - and automatic appointment reminders cut down the "did we still have you down for Tuesday?" calls too. Customer schedule sharing answers the question before it's even asked.

The verdict

Every "what time will you be here?" call is a small tax on someone's day. A visible schedule mostly makes it disappear.