My kids were 4 and 8 when I started. I also have 2 step kids that are here some days during the week, they're the same ages. I have Friday nights at 4pm until Saturday morning at noon completely to myself. (my kids go to their dads) If I don't have that time I'm no good come Monday... it's so important to have at least a few hours of kid free time in my opinion.

We took all 4 of our kids on vacation this past summer and I felt exhausted when I got back! No time alone... kids constantly! It was not a vacation in my opinion.

you need to have quiet time away from them every week.