Harmful tips

It's common to write useful tips on tire maintenance, but today we'd like to make a small exception. We should talk about harmful tips that are plentiful on the internet and don't bring anything but harm to both your tires and you.

It's enough to install only two new tires.
This statement is not only completely wrong but also potentially very dangerous. It directly affects the car's handling. Some car owners put only two winter tires on their vehicle, leaving the other two summer tires, despite it being prohibited by traffic rules. This is extremely dangerous, as it will inevitably lead to the car skidding, regardless of which axle the tires are installed on. The difference in traction is huge, so skidding will be inevitable.
It's also worth noting that installing less worn-out tires is recommended on the rear axle of the car, regardless of the type of drive.

In winter, you should regularly treat tires with silicone or blackener.
Such recommendations are due to the fact that during the winter period, there are many anti-ice agents and salt on the roads that have a detrimental effect on the rubber mixture of winter tires. This statement is valid, but not entirely true. The fact is that a black tire doesn't mean it's clean. It would be much more useful to regularly wash the car and tires and then use protective agents. But even with that, you shouldn't overdo it. If you "blacken" your tires too often, the rubber components may react unexpectedly. It's hard to say exactly what the reaction will be, as the components of the rubber mixture are different.

You should lower the pressure a bit for better snow passing ability
This advice comes from off-road driving. In extreme off-road conditions, it's indeed common to drive at lower pressure, but with one very important caveat - the tires are adapted for this, and such driving is done at low speeds. Off-road tires that allow driving at lower pressure have two or more layers of carcass, which really allows you to lower the pressure and increase the contact patch. Ordinary tires are not designed for this, and operating them at lower pressure will lead to a whole range of problems. In addition to uneven wear, fuel consumption will increase significantly, and due to the higher amplitude of deformation of the sidewalls, the likelihood of tire rupture will increase significantly.

Store tires in covers/bags
"Wash the tires and pack them in covers or bags"
Not at all! Tires should be stored in a ventilated room. What's the point of such storage if they'll be in bags? In this case, the "greenhouse effect" will render the tires unusable much sooner than their expected lifespan. This harmful effect can be especially exacerbated after washing, in which case water and the "greenhouse effect" will kill your tires if there's even a single non-through cut in the tread. This will lead to corrosion and deformation of the breaker layers of the tire.

The fresher the tire, the better.
There are already cases where, having an excellent tread and 90% of all spikes, car owners change tires when they reach five years. You shouldn't do that. Proper tire maintenance and storage implies using them for 5, 10, or more years. Manufacturers only make a reservation that after 10 years of operation, you should inspect the tires for cracks, deformations, and other damage incompatible with safe operation.