It's better to be safe than sorry:用心に越した事はない

When I spend time with my son outside,
I make it a rule that I bring extra clothes for him.
That is to say, my bag is always heavy…

However what if my son got dirty when I don’t have any other clothes?
Especially recently he has been very very active.
He doesn't care how much he gets dirty.

So, I think it’s better to be safe than sorry.