I think the answer to your question depends on a few variables:
- number of kids
- ages of kids
- temperament of kids
- usefulness and availability of partner/hubby
- age/temperament/usefulness of family members
For example: back when I had one bub, was on mat leave and hubby was available due to working normal days - it may have more trouble than it was worth to have my parents around. Actually it was. My sister - I could have enjoyed her company and help.
Fast forward to having two kids (2 years apart), one of who was an 'energetic' runner, then I probably would have most definitely accepted my sisters help - probably would have asked for it to. Night or day. My parents on the other hand - I may have considered their help if they had offered and if the kids were in bed when they arrived to help (eg for date night only not for day time care). I would have used my parents as a last resort.
It's all a mute point for me - no family around. I do have friends but don't call on them regularly - don't want to stretch the friendship.
Some times I am jelous of friends who talk about their family taking the kids a few nights a week/fortnight (and then sometimes complaining how hard it is still.... But seriously good on them for getting a break, if you can why wouldn't you).