Here is the single biggest killer of putty jobs:
DIYers in a hurry, metal window frames, quick repairs. glass window putty
Using putty is not squeezing a tube and wiping your finger. It is a craft. Done right, a putty joint will last 30 to 50 years. Done wrong, it will crack, fall out, or stain the wood within a single season. Here is the single biggest killer of putty