Shelly, in eight-nine years your ear canals may have slightly changed, the anterior wall contacting the earpiece is the TMJ which is continuously moving and could suffer degeneration and inflammation. There are other parts that can change due to bone growth, osteomas, etc. You wouldn't spend a lot having new impressions made and making sure that the new IEMs are the best fit possible, moreover if one of the old pieces is a bit too long already. Just my opinion