We recently completed an eavestrough cleaning and repair for a Dr.'s office here in Lethbridge. This photo shows why it's important for eavestrough to be sloped correctly. When the eavestrough is not sloped properly, water and ice can sit in the eavestrough. Over time, this weighs on the eavestrough and can cause it to sag. That is what appears to have happened here.
Unfortunately, not all installers will take the time to slope the eavestrough they install. Here at Chase Exteriors, however, it is our practice to slope the eavestrough correctly with every installation.