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In the case of traditional clamshell laptops, many are similar in construction, though some you open from the top and others from the bottom. More modern ultra-thin and convertible laptops tend to be simpler in construction but not necessarily easier to take apart. In particular:

• Some are glued together and almost impossible to repair whereas with others simply removing the back gives access to the motherboard and main components.
• Batteries tend not to be user-replaceable but built-in. They are custom assemblies shaped to fit within the laptop case rather than made out of standard cylindrical lithium cells.
• The keyboard may be built into the case top and the RAM soldered directly to the motherboard making them much harder to replace.