> Uptime Percentage : Service Credit > < 99.9% : 25% > < 99% : 50% > < 95% : 100%

These targets feel very very low nowadays.

99% uptime for email means 3.5 days/ year no email.

(although 99.9 = about 8 hours/year would seem bearable - but maybe not for a company like microsoft)

> 99% uptime for email means 3.5 days/ year no email

Depends on how it appears, if it was one or several large chunks that is much more disruptive than minutes per day. 3.5 days/year is equivalent to less than 15 minutes/day.

It sucks no matter how you slice it, but the severity/impact depends on more than the aggregate downtime.