Bunting is the easiest thing on this site to get wrong, because it is bought by guesswork and installed under time pressure.
Measure the run, do not estimate it
Walk it with a tape or measure it off a plan. The most common bunting order is short, and the fix on the day is knotting two lengths together where everybody can see it.
Then add for the drop: bunting hung dead straight looks wrong, and a gentle swag needs more length than the distance between the fixing points.
Spacing decides how it reads
Tight spacing reads as a continuous band of colour from a distance and uses more flags. Wider spacing reads as individual flags and is cheaper.
Neither is right in general. For a shop front seen from across a road, tighter is better; for a long festival run, wider covers more ground for the money.
Sewn tape, every time
Flags sewn into a continuous binding tape hold their spacing and orientation. Flags tied to a cord rotate, bunch up and fall off.
It is a small cost difference and it is the difference between bunting that still looks deliberate on day three and bunting that looks abandoned.
Storing it so it survives
Wind it back onto its card rather than stuffing it in a box. Bunting that goes away in a tangle comes out creased, twisted and slow to hang.
We supply it wound on cards per length for exactly this reason, and it goes up in a fraction of the time.