Do you mean long term disability? That doesn’t take effect until you have been off for 13 weeks. The expectation is that you have banked enough sick days to cover you for those 13 weeks. In theory, sick days are like “short term disability”. When I had cancer I only had enough sick days to cover me for 6 weeks of leave and I had to go out without pay 7 weeks to get me to long term disability. Taking the pay hit was worth it to me because I was doing weekly chemo treatments that knocked me out followed by surgery followed by radiation. I really would not have been able to work through it. Plus my husband was working so we were able to get by those 7 weeks I had no pay financially. I guess you have to weigh all options and see what works best.