Due to an EU regulation from 2017, you can only buy vacuum cleaners that have a maximum power consumption of 900 watts. However, it should already have this. Excluded from this regulation are: Battery vacuum cleaners, vacuum cleaner robots, combined wet and dry vacuum cleaners.
The wattage only provides you with information about the power consumption from the socket - i.e. about the power consumption. Accordingly, a high wattage also means more consumption and higher costs.

I can't give you a blanket answer as to which version of the vacuum cleaner is really better. This depends on the size of your four walls as well as your health and your individual needs.
Classically, bags are used in the vacuum cleaner. However, they have the disadvantage that you have to buy new ones regularly, which results in follow-up costs.
The alternative is the vacuum cleaner without a bag. This is only equipped with a collection container, which you must empty as soon as it is full. The disadvantage of a vacuum cleaner without a bag is that a relatively large amount of dust is stirred up when emptying it. This is not exactly beneficial for the health of allergy sufferers.

If you suffer from dust allergies or similar, I recommend a vacuum cleaner with HEPA or ULPA filters.
These filters trap dust particles as small as 0.3 microns. This way, the smallest particles such as pollen, bacteria and dust mite excretions won't even get to you.

If you just bought a new vacuum cleaner and it smells a little funny, don't worry. That smell will literally disappear into thin air.
However, if your bagged machine is older, here's why:
vacuum cleaner bag too full
dirty dust mite filter
sucking up water, liquids or damp dust
Even a bagless vacuum cleaner can spread unpleasant odours. With cyclone technology, for example, heat is generated by the rotary movement. If there are still moist dust flakes in the container, the vacuum cleaner will eventually start to smell.
If you can rule out all these causes, the motor may be defective. There is often an increase in heat in it, which burns dust or scorches plastic in the vacuum cleaner.
The easiest way to get your vacuum cleaner odour-free is to replace the dust bag. In addition, the trade also has so-called vacuum cleaner deodorants in the form of scented sticks, essential oils or pearls ready for you.
If you have a bagless vacuum cleaner, I recommend wiping out the container from time to time with disinfectant and a damp kitchen towel. This prevents the formation of unpleasant odours.

In addition to the dust bag, you should also regularly change the two other filters of your vacuum cleaner. These are the motor protection filter and the exhaust filter.
The motor protection filter is located between the motor and the dust bag compartment. It is particularly important if you have forgotten to insert a bag, if it is not seated properly or if it has burst.
Usually a motor protection filter consists of coarse fleece or mesh, which sits in a plastic device. How often you have to change this filter can be found in the instruction manual of your vacuum cleaner. Manufacturers often advise you to change the filter twice a year or at the latest as soon as there is visible dirt.
The exhaust filter, also known as the blow-out or micro filter, cleans the air before it enters the room again. You should also change it twice a year.
Some manufacturers recommend washing, drying and reusing the exhaust filter, whereas specialist lights advise against this for hygienic reasons.
Furthermore, some vacuum cleaners have filter cassettes for exhaust air cleaning instead of exhaust air filters made of fleece. This is often the case with vacuum cleaners with a HEPA filter. They are made of folded, fleece-like filter paper that traps the smallest dust particles. How often you change this type of filter depends on how often you use your vacuum cleaner.

I advise you to store your vacuum cleaner in a place where it will stay free from moisture and frost.
So the basement is not so ideal. However, if you have no other option, place a blanket or tarp under the unit. Under no circumstances should you store it in your closet, because you're bound to have sucked up small animals during the vacuuming process, and you don't want to find them in your clothes.
Usually, a separate closet for cleaning supplies is the perfect place to store your ironing board and iron as well.
In addition, some manufacturers offer their vacuum cleaners with a wall mount. This way, you can hang the device in a suitable place and it won't get in the way.

Under no circumstances should you dispose of your old vacuum cleaner in the household waste or bulky waste. Although both options are still common, they are prohibited by the Electrical and Electronic Waste Act. The reason for this is that many different small parts are built into vacuum cleaners, which can sometimes contain harmful substances.
However, there are a few ways to dispose of your old vacuum cleaner properly and free of charge if you use one of the following three options:
Returning it to the dealer
Use a private collection service
Drop off at a collection point for electronic waste
Handing in at an electronic waste collection point is often the easiest method. Almost every municipality has such a collection point. If you prefer to take it to the dealer, no problem. They are obliged by law to take it back. Most of the time they ask for a proof that you bought the device there.
In addition, some municipalities have e-waste collection services that will dispose of your old vacuum cleaner free of charge. They often drive to certain locations on fixed dates and pick up your e-waste.