From an email:

Me and my girlfriend went to your concert at The One World Theatre in Austin. We really enjoyed the show. I was wondering why your shows are so short and why don’t you have an opening act. The reason I ask is because we traveled over 500 miles to go see you perform and the show was only an hour and a half long.

My reply:

Normally our shows are about 120 minutes of playing plus a twenty minute intermission.
We don’t work with opening acts, because we enjoy playing for two hours and that time would decrease with an opening act and the need to make changes to the stage etc.

The One World Theater contracted us to play two shows of 75 minutes each. We played a bit more, but in order to turn over the house and do two shows in one night we can’t go any longer than we did.

When you buy a ticket for a concert you might ask whether the performer will be doing one or two shows that evening. If there will two shows, you can pretty much bet that each performance is not going to be longer than 75-90 minutes. Another dead give-away is when the venue is rather small. In a small venue we will usually have to do two performances in an evening.