How often should I use a sheet mask?

Lately, I've been so busy with work that I've been coming home late every night, and my skin has been in terrible shape. Yesterday, after washing my face after work, I was shocked to see my face looking much duller than usual under the bathroom light. I felt like I was really lacking moisture, so I quickly grabbed a pack I had at home and put it on. Then, I suddenly wondered how other people manage their mask pack frequency. My skin is so dry right now, I'm not sure if daily is good for me, or if two or three times a week is the right frequency. I've also heard that using too often can actually irritate the skin, so I'm cautious. Do you have your own specific mask pack frequency? If you have any special skincare routines for when your skin is in a bad state or you have an important appointment, please share them. I'm really curious to know how you all maintain your flawless skin.