I appreciate the post it is an interesting and somewhat controversial subject for purists. Here's a few things to consider. And please don't take it as me trying to put you off.
From room acoustics perspective treating reverberation in bass frequencies is difficult and requires big bass traps (ideally tuned traps). Adding a sub in an untreated room with uncontrolled reverberation is asking for trouble and could potentially kill what's good in a system. Most are not prepared to even use broadband absorption to deal with first reflections which is much smaller than bass traps.
My deadest room reverberation was controlled extremely well down to 120Hz below that it would go up few fold. However bass definition was great. But the room was heavily treated.
I've seen measurements of rooms that have reverberation in bass that is around and above 1 second. Won't name names. In other words this means each note rings for an extra second before it decays. I'm not talking about sub bass. Just bass around 150Hz. Adding sub bass energy would only make things worse, not better. And kill any definition.
Focusing on frequency range is absolutely the wrong way to go about it. The fact you can doesn't mean you should. It is matter of the environment and not needs or wants.
But let's assume you go ahead and do it. In most cases the subwoofer will be placed in the wrong spot. Where speaker placement is important, sub placement in relation to listeners and speakers is even more important. Potential issues other than the sub being too loud are issues with definition and timing.
Finally to properly integrate and have the most benefit from a sub it's best to high pass your main systems. This is to free up your main speakers from low bass duties so they can reproduce midrange better and not to cause phases issues potentially fighting and often smearing bass. This can be difficult and sometimes impossible.
When done right it can be transformational for a system, however most aren't willing to do it properly (placement, room treatment, measured calibration, high passing main speakers).
My post isn't trying to put anyone off using a sub, but it's to warn of difficulties. We already have many who are not willing to do basics with main speaker placement even though they spent good amount of money and wondering why their systems don't sound as good as they should. The last thing we need is people messing up their systems with poorly integrated subs.
Also worth adding. If you're source is vinyl you're unlikely to ever need a sub. If you're source is digital don't fret, even though some instruments are capable of playing notes lower than 40Hz not many ever do. And when they do your room will likely be a limitation to enjoy it. Not putting a downer, mine is.