How do you do it?

I am often asked "How do you do it?" when I am out with the three kids by myself. And I never quite know what to say. I know it isn't the most common thing to have three kids under 5 (but it isn't really uncommon either), and I do look young for having three kids (I am often told I look to be in my early 20's) which I am sure catches people's attention. But I am caught off guard when people comment.
I mean how do I do it? I do it because I need to. Because things needs to be done (groceries, errands, playdates, occasional lunches out, etc). I go out with three kids because I don't want stay inside my house all the time. And it isn't really as hard as other people seem to think it is. There are days where things are much more difficult, but often those are the days we stay at home!
I could tell them it takes a little longer to get out of the house so I make sure to plan extra time. I could say I choose to go out when I am having a day with more patience because knowing my limits is part of being a mom. I know to make sure that I have plenty of diapers and wipes in my bag when I go out. I bring snacks with me because a hungry kid is definitely a cranky kid! I am careful about how long I am out because tired kids are also cranky kids. It is about trying very hard not to sweat the small stuff. For example sometimes my kids run down the aisle at the grocery store. With one kid I would have yelled automatically. With two (or more) kids I watch to make sure they don't get in the way of anyone and stay in the aisle, but other than that I let it go. Is it the choice all would make? Most likely not but my kids aren't hurting anyone and they are causing trouble, they are simply being kids.
I don't know exactly how to answer people when I am asked how I do it. Often it is followed by a comment about how they have a hard time with one (or two) out and about. Mostly it is a compliment and I try to take it that way. And I never turn down help when someone wants to hold a door or let me go first in line either!