I use medicines only when it is necessary, but stocking up painkillers is maybe indeed a good idea to avoid facing supply problems. Just watch their expiry date, and do not take expired medicines. The expiry dates may have high variances in the case of various medicines. For example nowadays I took Flector Rapid and Augmentin. The Flector Rapid box I currently have is good until 2026, while the Augmentin box I currently have is good until 2023. Of course I take the latter in the upcoming days. The dentist told me to take it three times per day, until the box lasts. So I am not storing these medicines for years.