Most implants are still functioning between 10 and 15 years and there is NO reason to replace one unless it breaks.
That being said, there are two penile implant companies and both companies offer superb implants. There is a difference in overall longevity and this topic should be addressed with your urologist. Each implant has their advantages meeting the specific needs of any patient. I like to tell my patients that generally less than 1 to 2% of penile implants will fail per year.