The first time we went out after DD1 we were having dinner with MIL at Crown for her birthday and she was staying the night there so my mum sat in the room with DD1 and babysat while DP and I had dinner downstairs. It made me feel so much more relaxed knowing that she was only a minute away if I needed her. With DD2 we went to the movies at 7 weeks for 3 hours - she was easier and slept better than DD1 - so it also depends on the baby too.