Nurse practitioner here. Practical tips for maximizing your vial's usable life: 1. Keep it refrigerated at all times except when drawing your dose. Take it out, draw your dose, put it back. Don't leave it on the counter. 2. Use proper aseptic technique every time you access the vial. Swab the stopper with 70% IPA, let it dry for 30 seconds, then insert the needle. This is the single biggest factor in preventing contamination. 3. Don't use the same needle to draw from the vial that you use to inject. Draw with one needle, swap to your injection needle. This prevents coring (punching a small piece of the rubber stopper into the vial). 4. Inspect before every use. Hold the vial up to a light and look for cloudiness, particles, or color change. If anything looks different from when you first received it, don't use it. 5. Write the date you first accessed the vial on the label. This is your "in-use" date. Some compounders assign a shorter BUD once the vial is first punctured (e.g., 28 days after first access regardless of the overall BUD). 6. Never re-enter a vial with a used needle. Seems obvious but you'd be surprised.