There isn't always an easy strategy for knowing what to do about your child's invite to a friend's birthday party. Even though there's usually a right way and a wrong way to handle the situation, it's not always clear which is which -- especially as children mature. For most parties, there'll be clues you can follow to make sure you're holding up your end and not inadvertently offending anyone. In a pinch, just look at it this way: If your positions were reversed, what would you want a fellow parent to do? Keep this in mind, even if you aren't provided with clear guidance, and you won't go too far wrong.
You probably don't relish the idea of corralling a group of toddlers all by yourself, so don't expect the hosting parents to, either. If you're the parent of a toddler, plan on attending the festivities and helping out a little. You'll probably want to anyway. This is a courtesy, and it'll also give you a chance to socialize with other parents about the trials and triumphs of parenthood.
There's a maturity issue here, so attitudes can vary on how old is old enough for a pre-school child to attend unaccompanied. When in doubt, ask. It's also a good idea to ask before bringing younger siblings because you can't afford a sitter or don't want to leave them behind. This isn't a twofer, and having much younger children at the party can create an unnecessary disruption the hostess won't appreciate.
Check the Invitation Carefully
Invitations may couch the facts in friendly wording, but the nitty-gritty stuff is probably there anyway. If the invitation says plus parent or parents welcome, this usually means that you're expected to participate. If you can't find the important clues in the wording of the invitation, ask. If you're reluctant to ask for one reason or another, escort your child into the party and play it by ear from there. If you're politely freed from any additional participation, grab a couple of free hours and return at the agreed upon time.
Keep Your Child's Temperament in Mind
Even though some parents may consider a five year old mature enough to attend a birthday party unaccompanied, at that age, your child may feel insecure or frightened without you around, especially with all the excitement associated with these outings. If you've ever seen a kid completely freaked out by a clown, you know what we mean. You're the one in the best position to know how your child will behave, so even if the invitation doesn't expressly suggest your participation, and you may know of other parents who aren't attending, discuss the situation with the host. No hosting mommy or daddy wants to deal with a sobbing or dejected child on the happy day. Staying with your child may be right for your situation, and the host or hostess might well appreciate the extra help.
It may take a little gentle sleuthing, but you can usually discover the right approach. The key here is to anticipate what the host has in mind and make sure that it works for your child's level of maturity. If you think this may be a "mommy to the rescue" occasion, then make inquiries and adjust your schedule accordingly.