In my flying days, I found a skylight filter universally useful and left one on every lens. It also kept the condensation off the lens element.

I haven't made with/without photos to check, but from my profession in instrumentation, I have found that signals outside my bandwidth of interest are deleterious to the output of the sensor.. They cutback the signal/noise (S/N) ratio to the detriment of the signals I want to record. And they cannot be filtered out of the sensor output to restore that. So, yes, if you're not interested in those colors (frequencies) filter them out before they get in the lens or to the sensor.

That's why we now have smokeless powder; no more smoke and we can shoot the enemy (and they can shoot us) without all the moderating effect of gun smoke. Modern times.

Well, no. The Model 911 is still current and effective, and the .45 Colt round is effective. The Glock is a high capacity pistol, the magazine for which has been banned in many jurisdictions for political reasons. Further the 9mm Parabellum round has a lesser capability than the .45 Colt. The 1911 has withstood the test of time; we'll see about the plastic Glock.

But think of all the money you've saved in avoiding to have to buy film, and negative holder, chemicals and dark-room bulbs.

The gun didn't do the shooting, a person did that.

Not buying a new car is economical. I found that good value can be found buying a low mileage (less than 30,000 miles) used car, mostly especially, luxury models (e.g. high end of Mercedes models). These cars have taken a large depreciation hit and still offer a large part of their useful life. Most won't have the latest electronic gadgets but not a progress has been made on ride quality by the current models. Try to assure an accident free used car; no repaints to hid things.

What, exactly, is a refurbished camera? Does it start with a used, returned, open box, defective or demonstrator camera, or cameras recycled due to a know factory defect (or all of the above)? And what is done to to "refurbish" it? Apparently not done is to reset the shutter count. Who does the refurbish, the factory or factory repair, an authorized repair agency, or just anybody? Is there any standard warranty for a "factory refurbished" unit? Can one expect a life similar to that of a "new" unit? Does the refurb include the lens? Is the lens inspected for defects or "like new" performance?

Do you think humanity will die out?

"War is Hell" (Not an original quote) It is to be avoided, if at all possible. If it cannot be avoided, it should be with a mission, an objective, and an end plan, with overwhelming force and as short as possible. War is a waste, for the fighter and the enemy; it is better to talk diplomatically. The first resort after that should be to walk away.
From a Vietnam vet.

We walked out of Walmart with our purchases, without our cell 'phones in our hands informing anyone who would listen what we bought and where we were going next. We waited in line at the Donkin Donuts drive thru watching the car in from of us, not telling whoever would listen, texting our plans. We drove in traffic, watching and bemoaning what was happening, without keeping other people, mostly disinterested, about our delays and fustration. We mostly didn't re-end the vehicles we were following becuase we had our head down thumbing our "smartphone".
We spent time at home talking to friends and relatives about the day's events and didn't leave comments for strangers on NPR's news sites. We went to stores to buy and review purchases, not to the Amazon website. We went to the library to get reading materials and information, not doing searches and scrolling. We got information from friends and neighbors face-to-face, we didn't talk to anonymous people whose opinions were unknown or suspect on chat sites. Need I go on?

Why would one do this for normal photography? I've used infrared cameras for scanning structures and mechanisms for thermal efficiency and heat leaks, and other devices for night vision and survellience purposes, but these produce "fuzzy and somewhat indistinct" images. For the purposes listed they are useful but otherwise not very interesting.

Pegboard? Or maybe picture moulding (crown cove) with down wires? It sort of depends on whether the display is formal, casual, office, commercial (for sales), or museaum.

You didn't find the feature; it was never lost. You just discovered it.

If you buy a item in Germany, you pay and 19% sales tax (as a Value Added Tax). You can get this back if you export the item, but it is a paperwork hassle.