Context: iPod batteries are not designed to be removed or replaced by the user, although some users have been able to open the case themselves, usually following instructions from third-party vendors of iPod replacement batteries. Compounding the problem, Apple initially would not replace worn-out batteries. The official policy was that the customer should buy a refurbished replacement iPod, at a cost almost equivalent to a brand new one. All lithium-ion batteries lose capacity during their lifetime even when not in use (guidelines are available for prolonging life-span) and this situation led to a market for third-party battery replacement kits.

Question: Whose directions can be followed to interact with iPod batteries?
Answer: third-party vendors

Question: What did Apple originally tell consumers to purchase when their iPod batteries no longer worked?
Answer: refurbished replacement iPod

Question: What kind of battery does the iPod use?
Answer: lithium-ion

Question: Which iPod component did Apple somewhat inconveniently made non-replaceable?
Answer: batteries

Question: What type of rechargeable battery does Apple use in its iPods?
Answer: lithium-ion