I turn the phone off if the battery is probably going to drop below 40% while I'm asleep, but it's not low enough to charge when I go to sleep. Or when I'm switching batteries (I always have 2 batteries for a phone). Or in the rare instance that some hardware hangs.
Electronic parts don't wear out from being on, so the electronics in a phone should last a lot longer than you care about (I still have a couple of working MicroTACs - from around 1988 - they're museum pieces now, even if one has a battery that can still hold a charge for about 15 minutes of use).
So, yes, maybe if you leave your phone on all the time, it'll die in 2055 instead of 2053, but you'll be using an intelligent in-ear phone by then, so you won't care.
The battery is another story - if you treat it really well, it can last through almost 3,000 charge/discharge cycles - which is close to 10 years - before losing capacity, so if you turn it off every night, you'll make the battery last longer. But a new one in a phone with a user-replaceable battery (like the Note series) is $15 or less.