I never used them until recently, just a plain table for everyday and a tablecloth for holidays.
However, I just spent a whole lot of time refinishing our table as a pandemic project. I am currently using placemats at the two places we sit out everyday. I don't plan to use them when I have a table full of people, except for at holidays when I will use a tablecloth. I just want the table to wear evenly.
Even though four people sat at the table every day for the first 15 years we had it, and we had kids coming and going after that, I could tell a difference in the wear at the two spots just DH and I have been using day in and day out for the last 8 - 10 years.