Do I need to replace my silicone breast implants?

Only if problems. Silicone breast implants should be replaced if there are problems such as capsular contracture, infection, rupture or other issues. Also, if the implants have been deemed dangerous, such as with the pip implants, these should be exchanged as well.
No but don't ignore. There is a common myth on the internet that implants must be replaced every 10 years but I have removed implants that have been in for more than 35 years with out any apparent problem with the implants other than a desire for removal. Silicone implants do require intermittent surveillance for "silent rupture" and you should see a physician regularly with routine breast exams.
How old are implants. If your implants were put in more than 20 years ago, it is a good idea to replace them when you can as they will eventually rupture if they are not already. The newer implants are made to last much longer and do not need to be replaced unless they are damaged.
Eventually. I always tell patients that implants will not last forever. They typically have a 10 year warranty. Some people need replacement sooner, while others can go on for much longer periods of time before needing replacement. Eventually, you should expect the need a replacement.
Replace imiplants. Only your doctor can give you the answer. Currently it is recommended that you have an MRI every two years to look for leakage, and, if leaking, replace them. Most implants are warranted for 10 years from leakage.
Possibly . But only if you are having a problem with them.
Not a priori. Only if there is a known problem. Most pre-1992 devices better off replaced.
Yes, if it fails. Silicone implants last on average about 10 years. When the shape and size of your augmented breast change, you should have your surgeon check it. If there's a leak, the implant needs to be replaced.
Yes. Silicone implants should be changed out every 8 to 10 years as the implant shell undergoes a lipolysis reaction over time. Some surgeons recommend waiting longer until a problem develops but if you become ill with a fibromyalgia type illness, you should consider toxicity from a biofilm infection or chemical or silicone toxicity. See www.Thenakedtruthaboutbreastimplants.Com.