A battery you cannot replace is the product's expiry date

What follows is an argument about non-replaceable battery packs, and about where the received version of it stops being true.

Cells age whether you use them or not

Rechargeable cells degrade through two separate processes, one driven by charge cycles and one driven simply by time and temperature. Calendar ageing continues in storage, which is why an unused device can have a noticeably diminished pack after a few years. Heat accelerates both processes considerably, so a device that runs warm ages its own battery faster than an identical cool one.

State of charge during storage matters too, since cells held at very high or very low charge degrade faster than those held mid-range. None of this is a defect, and it means a battery is a wear item in the same category as a filter or a tyre.

What replaceability actually means in practice

A user-replaceable pack sits behind a door or a few fasteners and can be exchanged without special tools or skills. A service-replaceable pack requires disassembly and often adhesive removal, which is possible but priced as a repair. A bonded pack, sometimes with cells adhered directly to a structural part, can turn replacement into a hazardous and marginal operation.

The measurable part is this: the physical arrangement is the whole story, and it can be established before purchase from a teardown or a service manual. Where the maker sells a replacement pack as a part, the design intent was replacement whatever the assembly looks like.

Everything that dies with the pack

A pack usually contains protection and management electronics, and those can fail independently of the cells themselves. Management systems track charge state, and that tracking can drift so that a healthy pack reports incorrectly. Some devices pair a pack cryptographically, so an otherwise identical replacement is rejected or runs with reduced function.

Where the pack also acts as a structural element, replacing it means dismantling more of the product than the battery alone. A device whose battery cannot be replaced does not fail dramatically; it simply becomes less useful until it is discarded.

Safety, handling and disposal

Damaged or swollen cells present a genuine fire risk, and a swollen pack should be treated as urgent rather than cosmetic. Puncturing or deforming a cell during a clumsy removal can cause immediate failure, which is why prying near a pack is dangerous. Transport of loose cells is regulated, and rules on posting and carrying batteries differ by country and by carrier.

After the warranty ends, disposal is regulated in many jurisdictions and collection routes exist specifically because cells should not enter general waste.

Where a pack is swollen or damaged, professional handling is the appropriate route rather than a home repair.

What the design tells you about intent

Fasteners rather than adhesive around a battery compartment indicate that someone expected the pack to come out. Pull tabs under adhesive strips are an explicit design for removal and are documented in service instructions where they exist.

A published part number for the pack means a supply chain exists, which is more important than how hard the removal looks. Where a maker publishes a battery service programme, the design and the policy are aligned and the product has a longer practical life. Where neither parts nor procedure exist, the pack's ageing curve is the product's lifespan whatever the rest of it is capable of.

Published coverage skews towards whichever brands were willing to send samples out.

Judging this before you buy

Look for a service manual, an official repair programme or a published replacement part before assuming a battery can be changed. Check whether independent repairers advertise battery replacement for the category, since they follow what is practical. Consider how warm the device runs in use, because thermal design directly affects how quickly the pack degrades.

After the warranty ends, prefer devices that allow charge limits to be set, as avoiding sustained full charge reduces calendar ageing. For a product intended to last many years, battery serviceability deserves more weight than several of the features being compared.

The takeaway

Find out how the battery comes out before you buy, because that answer sets how long the product lasts.

Anything you cannot buy a spare part for is a rental with a long term.