Downtime planned versus unplanned how do you prepare

hey folks, been thinking a lot about system availability lately. we all aim for high uptime, but how much effort do you put into preparing for planned downtime versus focusing solely on preventing unplanned outages. for planned maintenance, like major upgrades, do you have specific strategies beyond just scheduling it during low-traffic hours. are there specific techniques you use to minimize the impact of planned downtime, or is the focus always on avoiding unplanned issues at all costs. curious to hear your approaches