Since upgrading to iOS 6 my iPhone 4S no longer seems to default to the mobile number of a contact for text messages. I have found after the fact that people haven't received text messages because I inadvertently texted their business line or their home line.
Is there a way to set the default number for text messages for contact? My iPhone syncs with Microsoft Outlook on a PC.
iPhone 4S, iOS 6.0.1, Email. Attachments. Verizon Outlook
In iOS 10, change that default by tapping and holding the button for a few seconds to open up that same pop-up where you can pick a different number.
Just note that when you tap the number, you will actually initiate a call. But, your iPhone will now remember that number as the default until you change it again. After you select a number, the button gets a new label to help you remember which contact method you’ll be using. It draws this label from the contact sheet, including any custom labels you’ve created.
https://www.howtogeek.com/272011/how-to-set-a-preferred-contact-method-for-conta cts-in-ios-10/
Are you sure this problem didn't also exist before iOS6? I am experiencing the same annoyance as you (i.e. texting in a rush and accidentally selecting a number that isn't text-compatible) but I don't recall a time where this problem didn't exist...?
It seems like a no-brainer feature for users to be able to set a default SMS contact considering that when there are multiple numbers, usually only one of them is a mobile and the others are either home or work....
Setting default number for text messages
