There's been a lot of good advice in this thread already, but I thought I may as well chip in
Without wanting to revive some quite heated old debates, you'll find there's a spectrum of views on here from the very purist "if you haven't taken the picture that day you're not a real PaDer" at one end to flagrant metagallery abusers at the other, with a lot of people (including me) sitting somewhere in the middle, which is probably summed up as the "try to shoot/post every day but don't sweat it" approach.
In terms of your specific question, I work 10-14 hours a day in a pretty stressful job and I have three young kids as well, so there's no way on earth I'd ever be able to shoot every single day, and I don't add extra stress to the pile by worrying too much about doing that, although I do try to whenever I can, and I do post a shot every day without fail unless I'm physically away from the computer, even if sometimes I'm so knackered I don't really want to.
I do most of my shooting at weekends as well, but I impose an informal "7 day rule" on myself, so I won't post shots that are more than a week old unless my pipeline has really run completely dry, which has only really happened once in my 5 months of PaD so far. I also carry a small digicam everywhere I go so I can grab shots as I run around, at lunchtimes and on the tube. Ray has described perfectly the change in mindset you have when you start doing that - I look at everything I see as a potential photo now and it's changed the way I see immensely.
If you're like me (you may not be!!) you'll find that your PaDing develops its own path and rhythm, and you'll find a way you're happy with for you and what you're trying to achieve. For me it's meant discovering some very talented people who do the same kind of stuff I do or aspire to do, and pushing myself really hard to try to catch up and/or keep up with them. I'm happy with that because I'm unhealthily competitive and perfectionist by nature

, and I get a huge kick from working to improve my photography and getting instant feedback by way of comments and votes (which are VERY addictive, be warned!). Just taking and posting any old shot of a household object when I stumble in from work at 1 in the morning seems pointless to me so I don't do it, but for some people that's exactly the discipline and challenge they want - find your own path and you'll find PaDing is a great experience.
Good luck!