For years I have had problems with earphones sticking in my ears. The rubber tips just never worked well for me. And no matter which size I tried I would think they worked, but I would be constantly adjusting my headphones. They basically never fit nor stayed in my ears.
About a year ago I got a pair of beats 3 headphones that I loved, but they never stuck in my year. I was literally considering getting custom ear pieces made so that the headphones would fit. That is when I started google searching, and I found Comply Premium Earphone Tips.
They make various memory foam headphone tips. You can get them in 3 packs of small, medium and large, or in single sizes. I got the 3 sizes and the medium seem to fit perfectly. You squeeze them and insert them and they re-expand and fit. Now I can walk for an hour and they are still comfortable and never need to be adjusted.
The Comply earphone tips are so good that I feel like Apple should buy them and include them with every set of earphones.
Then I was given a pair of 1More Lighting headphones for my iPhone X and was also having the issue with the rubber earphone tips. So I ordered Comply Earphone Tips and they fit perfectly and sound amazing! What a difference!
Now I got the Sport versions as I use them when I walk and sweat and they are supposed to make a sweat barrier, but they have many different kinds that I have not tried, but I would be willing to.
These are literally the best thing to happen to in ear earphones in a long time! I LOVE THEM! My highest recommendation.