Once they're mobile, it gets many times harder. It goes something like this:

- Newborn to ~6-9 months: not mobile, and not too demanding either (especially early on)

- 6-9 months to 3 years: mobile and constantly trying to hurt themselves

- 3-5 years: mobile, mostly safe, but not understanding what "no" or "I'm busy right now" or "I'm on the phone" or "I need privacy" means; also not napping anymore, which means you lose that daily couple hours of bliss

- >5 years: gets progressively easier as kids begin to get independent and (somewhat) reasonable

Of course, this timeline is different for every kid.

We have four kids ranging in age from 1-7 years old. I work from home, but rarely am I in charge of taking care of the kids (right now, for instance, my mom is watching them while my wife runs errands). On the occasions where I am solely responsible for them, I consider any work I get done to be a bonus.

You've got such a great mom to help you out in this way.

We're incredibly fortunate to have family nearby that is able and willing to help.

Much, much easier with just one infant. I have a 5-year-old, 2.5-year-old, and 6-month infant at home. I'm considering keypad locks for the bedroom and office. I take calls from the closet or from the inside of a car.

Put whiskey in their drinks and you'll be fine

Infants are a dream compared to toddlers. Apart from when they need to be fed or changed, infants do practically nothing and don't have to be watched constantly.

Toddlers, on the other hand, are little balls of pure energy that get into anything and everything they can touch.

Ha, I see others have written great responses to this already. I have heard not all children are difficult. I personally can't imagine such a thing, but I have one of those "spirited" children. The comment below from syedkarim about putting locks on the doors made me laugh. I tried that with limited success.

Yup, between 1 and 5 they’re mobile and active enough to require constant engagement but mostly not self-reliant enough to find it themselves. It varies a lot based on the child though.

Much easier if the infant isn’t fussy. Kids have “features” that light up every few weeks.

It was hardest for me around 3... my son just wanted to play all of the time.