What a late cancellation actually costs you

Twenty past six. Phone goes. "So sorry, something's come up, can we do Thursday?"

"No worries," you go. And you mean it, that's the annoying part. Then you sit in the car for ten minutes working out what to do with an hour you can't sell to anybody, and drive home.

Right. Let's actually do that sum.

The one you did in your head

One session. Forty-five quid. That's where most people stop, decide it's not worth the aggro, and fire back a thumbs up.

The one you didn't

You can't shift a half six slot at twenty past six. Nobody's coming. That hour hasn't moved, it's gone.

And Thursday? Thursday was happening anyway. So you've not picked up a session. You've dropped one.

Grand and eighty. That's not shrapnel down the back of the sofa, that's a fortnight's graft, handed over forty-five quid at a time, to people who genuinely feel bad about it.

Why you never charge it

And before anyone starts, it's not because you're soft.

It's because you've got nothing to point at. No rule, nothing agreed, nothing in writing. So the second you think about charging, it lands like you're having a go. At them. On that day. About that excuse. And who wants to be the one invoicing a woman whose kid's been up all night being sick?

Get a rule and the whole thing goes away. A rule can't be personal. It was there before anyone's kid was ill. You're not making a call on the day, you're just doing what you both said you'd do back at the start. Much easier sentence to get out of your mouth.

One that actually works

It's that last one that lets you have the first two without feeling like a wrong'un.

You don't need a feature for this. No "notice window" setting, no app at all. You need one line in your terms, and to say it out loud, once.

Eight of those a year and the app's paid for itself. That's not the point, but it is the maths.