Nothing. There's no reason you can't keep doing what you were doing, and you could probably argue that the time it takes for your computer to boot up is probably ample time for the DSL modem to train the signal and make a connection. Or at least you have a good head start on the process.
If you're the only person who uses the computer and DSL modem, then do whatever works for you and don't worry about what other people say.
I have had my Dsl modem for 3 years now & I have always when finished would turn off my modem & also my pc.......now I was told it was okay to turn off my pc when I am done but, to leave the modem on & I did this for a few days & it made me nervous & plus the modem was so hot..........I can not understand this as, we can shut down our pc & then when we are ready to use it again, we can turn it on & it boots up & so what is the problem with doing this with the modem as, it is little & does not have as much in it as, a pc does???

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