It's always challenging finding the balance and giving advice to others for family and work, especially since everyone is different. This is one of those topics where if you polled a room of 5 people, you'd get 6 different answers, and none of the answers would necessarily be wrong. Obviously not every answer would be acceptable to every person, but they each would contain their own respective blend of pro's and con's.
I love spending time with my kids, but I also enjoy the statisfaction of working as an engineer. There are days where I am excited to get to work so I can tackle the latest design/construction issue, and other days where all I want to do is go to the park with my kids and watch them play.
I think everyone has a certain "need" for stimulating interaction with others. Some people find this stimulation through their interaction with their kids, others find it in the lab/office/work environment, and a few more find it through sports/activities/games. It's just important that you find the balance that is right for you. It is also important to find the balance between the interaction you want and the interaction you need as well as with the interaction everyone around you needs (kids, spouse). You shouldn't give up what your kids/family need simply because you want to do something else.
You also have to balance this all with your "obligations" such as being a good spouse and parent as well as meeting the needs of your employer and/or clients.
You may have noticed I have completely left out the financial aspect of this, and this was intentional. You will find that once you determine your own "balance," the financial aspect always seems to work itself out.
I don't think anyone has developed a perfect system, we all just find a way to maintain.