My 3 cents on:
"Should I turn off my computer so that it does not wear out, etc."
Here it is like this:
=> Hard drives.
Overall, parking, stopping, warming up and cooling down the drive is not the most fun for him. The drive prefers to be turned on once and walk 1000 hours rather than turned on 1000 times in just one hour.
Only that the impact of this is PRACTICALLY MINIMUM.
It is much more important to ensure zero shock for the drive and its good cooling [some companies have / had hot plates in the HDD, which above 55'C sometimes do a "snap" and the drive no longer reports in the BIOS].
Regarding the HDD, screw it to the housing with all screws and ensure proper ventilation of the housing [airflow, ie minimum fan at the back and a gap at the front of the housing].
When necessary, you CAN [and for practical reasons] turn off programmatically [not with a plug-in] and it will be OK.
I see. I do NOT recommend turning the disc when not needed.
Note: Do NOT use any soundproofing of the disk based on placing it in a foam casing. Heats up and damages faster.
=> Other components.
Here, the working time and working temperature are practically important. Of course, there is such a thing as mechanical stresses due to heating / cooling, but in my opinion it's best to just keep the temperatures low enough. We will then gain longer computer operation time and slight temperature differences. Simple air cooling will do [NOT water or miracles].
=> Power
Adequate power supply is essential today. Computers are drawing more and more electricity and companies are cutting costs. I would also recommend having a good power supply. It is worth reading here and there which companies have good power supplies. There is also a black list of power supplies on Elektroda and a lot of topics on this subject.
When choosing a power supply, the following should be considered:
=> quality of workmanship [information about a given company] - this is a very important factor. NOT always a branded company stands for the best super hyper power supply. [here perhaps some Chieftec models are a good example; you can find cheaper power supplies not inferior]
=> appropriate maximum power [it is better to have a few watts more, but NEVER buy "butt joint"]
=> saving money: it is worth having a power supply with an ACTIVE PFC and preferably with a signet> 80% efficiency. The more fitness the better. The cost of the power supply should pay off after several months / years of intensive use.
I would like to add that my computer had ModeCom 350W and now in another thread I am asking which capacitors I should replace xD I will add that Modecom itself started to smoke more and more after a few years when the computer was stand-by [turned off]. I don't think you need to write what would have happened if I hadn't been home.
Cheap power supplies are NOT the best.
=> Overclocking
It is NOT recommended to overclock a computer that has a stable running time of 24/7/365 / x years.
This is very good for extracting FPS in games and where we can supervise the computer.
=> Prolishness
Today's computers no longer consume 60W, but from 200W to even 400W and more.
So it's a good idea to turn Hibernate on and off from time to time. After Hibernation, our programs will be available again.
If we want to leave it for> 20 minutes, it is worth turning off the monitor or the whole thing.
If we have any servers, all the pros and cons have to be considered individually.
If someone goes only with low power consumption, then only Atom CPU laptops. They charge 30W. Only that laptops are more difficult to repair / upgrade [you will not put in a new graphics or music card, or even 3 disks there].
=> UPS. Power cuts.
There are 2 things here. The power industry can fund surges for us, but the strip can fund us to lower the current. Even a weak plug can do a misfortune.
The slats are OK, but you need to be smart. Let others comment on the subject of varistors [if they have not already done so].
For purists: Even a normal fuse has a certain resistance, so it also GREATLY lowers the voltage and increases the resistance of the cable.
UPS. NOTE: When we have an active PFC power supply, our UPS MUST give an EXACT SINUSOID !!! APPROXIMATE is NOT good!
The UPS MUST have adequate power. Note on VA and W. The difference between them is similar to the difference between GB and GiB.
=> Components.
If the computer is to be the ONLY Linux server, IMHO is NOT worth loading a GeForce 9800GTS card there. You can lower the processor clock speed, but it is not always 100% successful. [I had to "slide" down to 50% due to the bulging capacitors and sometimes my computer does not get up right away; although after commissioning it is extremely stable] Nevertheless, it is a good method to extend the service life.
=> Testing
It is worth using a good cooling system, make sure that there is air flow, check the computer's temperature. There are CPU Stress Test programs [turn on AFTER cooling is OK]. You can turn them on and monitor the temperature. Then it will be known what the "worst case" is.
In general, the cooler the better. [but also without exaggeration; below + 5'C fear is booting the hard drive] If it is OK for a week, it can be considered OK ;-)
In general, a computer is a collection of different devices, and each has different requirements. [e.g. disk vs CPU]. The most important information is above, although the topic is almost endless. Overall, it's a good power supply, cool in the housing, not overloading the system [eg. combine with OC] and not "throw / knock" the computer [especially when it is on]. So some power supply, good cooling and not to go crazy [turn off less often than every 20 minutes]

.
Let me just add that by leaving the computer turned on for the whole day / night and still connected to the Internet, you should also think about its protection against malicious people [viruses, firewalls]. Often times, good network configuration and good habits are helpful. Often, viruses can generate BSODs and other crap in Windows, although the hardware is OK.
Good luck!