I have been brought up in a generation where we were taught never to throw away things that could be of use to anyone. As a result, I find that many people, including I, have too many unnecessary things in the house. I used to think that every house should have a storeroom, because doesn't everyone have lots of things to store?
If you walk into a kitchen shop, you'll find all kinds of utensils; do we need every one of them? If you walk into a furniture shop, do you think that every home should have one of every type of furniture - a coffee table, a cabinet, a sideboard, a computer table, etc? We fill our homes with clutter just because we have been led to believe everything is a "necessity". That is why we buy things as soon as we find a nook or a corner to place them in. When we want to make room to buy even more things, we place them in storage - out of sight - so that we can continue to buy more things.
Word of advice: start giving away or throwing away things that you don't use and you'll find you have less housekeeping to do. Warning: this is very painful to do and requires great resolve. It will be accompanied with a feeling of loss and possibly regrets. Few people actually succeed in making a significant impact when it comes to clearing clutter; they always find a reason to keep things. After all, that's how the clutter builds up in the first place. Back to square one.