Flying domestic out of IAH - how early do you usually arrive?

Hi all,

This morning I was scheduled to fly from IAH to SLC at 9:50am. My flight was out of terminal D and the United app instructed me to go to Terminal D, door 104, and use the baggage drop shortcut line for me pre-paid golf bag.

I arrived at 8:50 and there was a super long line in the premier line, the regular line, and in the baggage shortcut line. I waited in it for twenty minutes before deciding to call an Uber and send my golf bag home. The Uber took awhile but it finally arrived. I sent my clubs home and rushed to the gate. I ended up missing the boarding window by a minute and am shipping my golf clubs next day air to the hotel I’m staying at.

Should I forever ignore when United tells me to check my bags anywhere other than terminal C that has tons of gate agents and kiosks? Should I start arriving for domestic flights earlier? Should I have stayed in line and got myself and my golf bag onto a later flight?

Thanks for any insight.