I think that the society where we live makes us believe that what we want IS what we need. In fact, the perceived obsolescence is the perception that an object isn't anymore fashionable, so you want to change it. Then, in economics the planned obsolescence is the process studied from the producers that causes an object to doesn't work after a certain time.
Some pages where you can know more about the obsolescence are https://en.m.wikipedia.org/wiki/Obsolescence and https://en.m.wikipedia.org/wiki/Planned_obsolescence

I partially agree with you, I think that nowadays we are really influenced by our society and the planned obsolescence in economics and marketing is real but you have to think with your mind and make your own choices.
Trends are real and influence every day our society but thanks to education, good values and self-decision you (but also a lot of people) can buy things that you like and mostly need and want, not that everyone has.
I know that is cool having the last model of mobile phone, new clothing, expensive bags but is it really what we need?
The perception of obsolescence is yours not of the society, you make the choice, the society/industry only offers new products, items, possibilities… that it is normal they are better than the old ones, it is called development.
Planned obsolescence is real as I said but I can think only for electronic devices and not for everything, also I think it is not properly legal and if you have this suspect then avoid to buy this kind of products.

I think you're right about the trends, in fact I don't really follow them, but a lot of people do it. I'm not sayng that all the people wear fashionable clothes or have the coolest phone, but many of them do it, maybe because they want to or because advertising has convinced them. Indeed, advertising focuses on people's desire to change things and to always have something new and it often succeds, perhaps even deluding them about the reality of product.