Many times someone doesn't have UR or UA miles but needs a united award.
Aeroplan, Miles & More, ANA, Singapore are all great ways to fly on United metal, often without YQ (domestically). These programs have different transfer partners, such as MR and SPG.
This thread is for detailed information including fees, change policies, mileage requirements and other arcana relating to booking awards flights on United Metal.
The goal is to wikify the knowledge so that it can be a quick reference for those looking to book awards on United using various points programs. Having it laid out in a simple manner will help DDF members avoid gotchas and costly mistakes.