Never be afraid to ask friends for help; whether it be advice or physical human power. Your friends are an amazing resource, but you have to take care of them or else like our polar ice caps, they will begin to disappear from your life.
There are plenty of online communities on social media or forums to go and be an active member in. These places can be great to go for advice, sourcing suggestions, etc. I am a member of Costume People as well as another Facebook group for graduates from the university I received my MFA from.
Recently I have designed a project where I had no shop but needed a lot of alterations to happen. I was lucky enough to have some money in the budget to pay an assistant, but I needed more help for a day. I sent out a call for a four hour time period and promised pizza. I feel four hours for pizza (and some other tasty treats) is a fair voluntary ask.
If I needed more than four or five hours of help I would probably try to find another way to "pay" my friends. One way I find to be a good option is comp tickets if they want to see the show, or a special thanks in the program if the due date hasn't passed for submissions to the playbill.
One thing you have to remember is your friends are being generous with their time so you should be generous with whatever you can in return. If you can't do something at the time, let them know you will show up for one of their calls.
The Beatles were right, "I get buy with a little help from my friends..."