We have had repeat customers call but through different phone numbers, so their info doesn't populate automatically. I have worked with other systems where you can type the customers name or even their partial name only using a few letters and the system can generate suggested names already entered in the system. This makes it easy and fast to locate repeat customers. I have found that if you do not spell the customer's name correctly it can look as if they are not in the system. This is especially helpful with how many different ways there are to spell names and can help prevent duplicating profiles. Not sure if this is/or could be an option for service titan.
To add to @egamby84 idea - it would be nice to possibly integrate this into the function (CTRL + ?) - if we start to type a customer's name it could pop up with a link - or offer customer search as an option to then search a customer. Not sure how data could be pulled on the back end, but in my head this seems the best way to integrate this idea.