Many people will be familiar with the three-legged stool philosophy in life - the most common manifestation being in the well known toast 'health wealth and happiness'
The general principle is that of a milking stool. Ideally all 3 legs will be complete and intact. In reality we will often be on 2 legs with relative comfort - however by the time we are one one leg, things are starting to look a little shaky.
In the commercial lending/borrowing environment, the 3 legs will mostly comprise past performance, future prospects and security available.
