There's not much "margin of error" allowed from a good sounding fit, to sounding really awful.

In fact, they do such a great job that I have to either mute my music or take them off if I need to interact with family or exist outside of my musical isolation....not a bad thing!I don't typically write product reviews, but I have been SO impressed with these, and I also didn't want people to almost make the same mistake as myself and dismiss them without a proper fit

The overall fit of the 315's is excellent

Could not get a good fit, so sound quality was compromised

I purchased additional flang tips on amazon to get the best fit in my ears

If so, you're not getting a good fit and you should try a different sleeve or re-seat them

The removable wires are great and allow for excellent fit and adjustment.

I really enjoyed the fit and feel of the product from Shure

I found the perfect fit

Luckily the Comply T-100 aftermarket foam tips I used on my x7i's were a perfect fit

I see a lot of reviews talking about the lack of bass, most likely that can be caused by bad fit and or the sourse of your music

Good sound and nice fit, but the price, the build quality and longevity of these earphones together with the lacking Shure service makes it hard to like these

Find the right fit, let them break in and then decide.