I have always bought sennheiser earphones both plug and over the ear type, they provide me with the rich deep bass and mid tones in music I enjoy listening too.
They arrived in no time and where exactly as advised.
After Googling to find where I can buy earpads and discovering so many places offering far too many (I only needed two) and at ridiculous prices, it then occurred to me to actually see if Sennheiser sells them. Keep it simple.
Fortunately, Sennheiser does sell replacement earpads.
The process to buy and receive was simple.
The price was okay.
I don't know how many years it will be before I need to replace these earpads but I will simply go straight to the Sennheiser website. The headphones themselves are many years old now and still working as well as they always have.