My son was born at 25 weeks. I didn't want my family to be there 24/7 but it was extremely important to me that they meet him asap. In my case, it was the day following his birth as day 1 was spent trying to stabilise him.

You will find that NICU's will allow visitors, usually very limited numbers by the bedside and the length of time is usually dependant on how long the parent wanted them there. With my family's first visit it was 2 at a time for only a couple mins. For many of them it was a gut wrenching experience, something they were far from prepared for but they were all glad (as was I) that they were able to meet my little man when they did.