you can get 99.9% uptime w/ a service guarantee if you are willing to pay as much as your rent/mortgage (more or less depending on how much squalor …or NOT :) you live in)
sometimes IT ISN'T the CABLE MODEM
for about 2mos my cable modem locked up almost every day... I was getting VERY ANGRY... I called the cable company they sent people out 3 times
(each tech more or less blamed the last tech...or ME which kinda pissed me off. they swapped cables (redid connectors out side/inside the house) they even switched modems
none the less the cable modem locked up every day
finally i called again... and someone there at the cable company FINALLY (apparently cause they said there was an error in the provisioning... and when they fixed the provisioning the problem went away.) double checked all settings on their end.
it was ticking me off ...been pretty good since... not stellar but for residential service certainly passable.