My mother lives in a memory care unit. My biggest problem is they don’t have a nurse in the unit 24/7 they check it every 2 hr. Is that bad?

What is in your mothers contract with her facility? What frequency of attention is your mother paying for? Is this mentioned in her contract?
I’m just assuming from the different answers you’ve received that it could be some facilities charge more than others and possibly claim they provide more service.
Is there a state requirement? In other words are they obligated to check on patients on a regular basis or they lose their license? It seems like there would be some standard of care you could depend upon.

The MC facility that Dad was in had a nurse on-site 24-hours. I popped in as late as 11:00 pm, and she was there. Never did try to check after that, but I trusted them, and also spoke to nurses early in the morning that had pulled overnight shifts. Oh, and my understanding (and belief) was that they did bed checks every 2 hours, and more for patients experiencing some trouble. I know they checked on Dad more frequently at times.

Zupa, my experience with Assisted living mirrors yours. the only time I see 24 hours nurses is when there is also a skilled nursing facility in the same building. My experiences (with 3 facilities - 3 different patients) is mixed. One had 'hourly ' checks on the residents. Another had NO checks - but the patient wasn't in the memory care section. To be honest --- my experience was the aides did a LOT of sleeping on the night shift! Many of them work 2 full time jobs and they are exhausted. The one that wasn't in memory care , did need help a few times. She called and called and no one came --- except the resident in the next room. She then called out in the hall for help, no answer. She then called the main number--- no answer. Ultimately, she called 911. the EMTs came, rang the bell, knocked on the doors and called the main number -- it took 10 minutes to arouse the sleeping aides. There are only 2 on at night for about 60 residents in my area. If you can get them, they call the on call nurse if there is something they can't solve.
Frankly, it isn't ideal, but that is one of the big differences between assisted living and skilled nursing. Fortunately, my 3 care receivers didn't have any major medical health situations. AND, in all honesty, it seemed better than what a live in could do as that caregiver also needed sleep time.

As long as there is "access" to a nurse and there's sufficient ancillary staff (nurses aids, caregivers, attendants) who could summon medical help or give medical help if needed, it should be Okay.

I believe the facility my mom is in , the nurse is not there during the night-sleeping hours but the c/g's and an administrator always are.