For a cellular modem connection - about 0% of the time. In any of them. If it stops working you have to dive into the guts of the cell modem connection manager which is third party and _NOT_ subject to such windows niceties. Considering that a lot of them are written cross-platform to support Windows & Mac nowdays you should be expecting guess what - config files. Text ones. No registry.
Fix by "repair connection"... Bwahahaha