Here's an optional rule for Night's Black Agents to really bring out that old-boys'-network le Carré flavour.
In addition to the 55 General Ability points characters start with under the DUST rules, characters who start the game fifty or older gain bonus General Ability build points, depending on their age:
These bonus points may not be spent on Athletics, Health, or Hand-to-Hand. In games which also use the BURN rules, spending bonus points on Stability is also prohibited.
Bonus points spent on Network and Sense Trouble, however, are doubled.