Comcast

Six months.

More hours spent with fruitless calls to Comcast customer service than I can count.

More first-name-only customer service reps than I can count, many of whom barely speak English. 

the result?

nothing, nada, zilch, zip. The problem (poor video signal, "node" problem) persists.

Comcast customer service SOP:

• tell us that it's fixed (even though it's not)
• tell us that they'll fix it (even though they don't)
• point out that there are other channels where the signal is OK (ignoring the fact that the channel that we want to watch is unwatchable because of pixelating video and inaudible sound)
• charge us full price for cable TV when at any given time there's a 90+% chance that the program that we want to watch is unwatchable
• when all else fails, tell us that we can ask for a credit for those times when Comcast didn't provide the service that we pay full price for (#hours/hours in a month x monthly rate)  
• basically, Comcast customer service SOP is to ignore the customer and ignore the problems with its own signal

Do yourself  a favor. Don't do business with Comcast.