UPS Sensitivity. What's the best level to set up and why?

[ThunderZed]

I've just got a 540W and pure sine wave Cyberpower cp900epfclcd to... "take care" of my PC, I mean I did't buy it to save my job in case of brownouts/blackouts but to preserve my PC's components to ensure them the longest lifespan.
That said I'd say to set my UPS Sensitivity up to the "high" level according to the attached scheme but I'd like to listen to your opinions about that. Afaik the main downside to set it to the max is that the ups battery lifespan will be shorter, won't it? If yes, are there other downsides to know?

I give you the operating scenario. My cyberpower has to supply a CX450 Corsair PSU and my PC runs in a new building so electrical wires are in very good conditions, anyway I can't say anything about electricity "quality", I just can tell you the "input" value my cyberpower shows is 236V.
Consider that I usually spend my summertime in another house which is older and brownouts and blackouts are quite common there.
What do you suggest to me in these two different scenarios?

[nightfire]

Go for the high sensitivity. As this UPS type is line-interactive, it means that when there are issues on the mains it has to actively switchover to battery operation. This "sensitivity" settings are simply the setpoints on which it initiates the switch, which itself also takes some milliseconds.
Depending on the root cause of your outage, you will want a fast response to it, especially when the Powersupply of your PC otherwise goes bonkers because of sudden undervoltage.
I do not see where this shortens the life of your UPS- the frequency of brownouts in your area that cause the switchovers are...

[ThunderZed]

I do not see where this shortens the life of your UPS

Sorry but I can't write english very well I wanted to establish a link between the higher ups sensitivity and the higher probability its battery will run more frequently, so it's not sure but just a "tendency". My guess is setting up this level to the max will make difference only during summertime because I guess the electricity "quality" is worse in my other house and that will shorten cyberpower battery lifespan. I hope I've explained it better

[nightfire]

The problem with tear and wear in an UPS battery is not the switchover thing, but constant recharging. So the batteries probably only will get anyway a life of 3-4 years- usually some time powering a load is in this case not much more shortening their lifetime in addition to the charging.

[Halcyon]

The question whether or not to select a higher sensitivity depends on your location and how good the electricity supply is there.

For some people in areas with fluctuating voltage or frequency, or where certain devices cause line noise (like power tools etc...) a higher sensitivity might lead to the UPS constantly switching to battery. This might be undesirable, so users have the option to lower the sensitivity and accept slightly dodgy power. Any half-decent power supply will handle this without any problems.

If you're in an area where power supply is reasonably stable and it's not constantly going to battery, then high sensitivity is perfectly fine.

You might choose to adjust your upper and lower voltage limits to be as close to your nominal supply voltage as possible. On some UPSs (like many of the APC models), these voltage thresholds are separate to the sensitivity level.