My son was 3 and my daughter was 1 when I started. Introducing a 3 year old to daycare in his home was challenging...very. But, my 1 year old only knew that, so it was always easier for her.
Balance was difficult. And at first, you often have younger dcks, since they're usually the ones looking for care, but as everyone grows with you it gets easier and easier and you take one young one at a time as kids go off to school.
Lots of free play. It's good for kids to play on their own and you're no use if you're burnt out. It's real life, so like someone else said get work related stuff done during the day as much as possible to have your evening to enjoy your children one on one.
It gets easier. Trust me. Mine are now 7 and 5 and I survived the early years and am now enjoying the quiet time of less kids in daycare, since mine still count in my ratio.