Tip for car services?

Looking for some input on what to tip when using a private car service. I’ve always done a few dollars per bag, but at least $10 for exceptional service because it’s normally just myself and one bag. I’ve booked Tiffany for the first time next month. The invoice says “gratuity 20%”. I didn’t pay that in advance, but are they suggesting 20% of the total cost? That would be $20. I’m fine with giving whatever is appropriate but just want to check what others do in case I’m way off.

 

I see it's been a while since you've posted, but I just wanted to ask if anyone has recently used any drive-up oil change places with twins in tow? I'm trying to avoid unloading both kids just for a quick service. Also wondering if anyone's tried scheduling mobile mechanics—do they actually show up on time and finish quickly?

 

We had a similar issue last winter flying out with toddlers and tons of luggage. What helped most was using bookinglane.com airport transfer since the driver met us inside with a sign and helped with all our stuff. Way smoother than waiting for a rideshare or juggling car seats in the cold.