Start with two recipes you want to eat
A recipe search can turn one inexpensive bunch into several new purchases. Pick two dishes that were already plausible for your week, then estimate how much herb each one uses. A garnish of three sprigs on both dinners may barely reduce the bunch, even if it looks like thoughtful planning.
Decide whether a second use is realistic
Compare the amount those meals need with the bunch sold at your shop. If you'd use only a few stems and have no realistic plan for the rest, a smaller pack, a dried seasoning already at home, or a different recipe may fit the week better.
Put the bunch beside both meals on the list. “Parsley for grain salad and Wednesday dressing” tells the cook which stems are still needed later. If the dressing is optional and commonly skipped, be honest about that before buying the herb for a second supposed use.
Check whether the plan worked
At the next shopping trip, ask how much was actually used and which dish people enjoyed. If the salad used plenty and the dressing went untouched, keep the salad and buy a smaller bunch when available. The point is a better ingredient decision next week, not inventing another parsley dinner.