@Noch based on the replies in this thread I chose to only take carry on. When we landed in LAX, the flight attendant instructed everyone to pick up their bags with no exceptions. I think if I had taken checked luggage I would have missed my connecting flight. I still had to run from the international terminal to terminal 7 and only just made it in time. Customs took about 30 mins but my flight into LAX was late so I had about 40 mins to make it.

The layover time is 1 hour 40. I spoke to someone from United Airlines today to ask what will happen with my bags as I was concerned I wouldn’t have enough time to collect them and go through customs etc. She said they have waivers for passengers with short stopovers which means my luggage will go straight to my destination. My flight is in a couple days.