How long does an internal battery last?
It’s not possible to give a definitive answer, as the battery’s life ultimately varies depending on its manufacturing, storage, use and other factors. However, personal experience and some double-checking online indicates the usual lifespan is somewhere between five and ten years from the time of manufacture. My original copy of Emerald was closer to ten.
As production of Emerald in the past ten years has likely been very limited (or completely non-existent), it’s possible that your game will arrive to you with a dead battery. I won’t speak in absolutes though, since I obviously don’t know its precise circumstances.
Aside from the clock stopping, are there any additional side effects of the battery being dry?
There are some GBA titles that require power to save, but fortunately there are no Pokémon titles among them. The only features you’ll lose are time-based — for example, you won’t be able to grow berries if the internal battery is dry.
The game will actually warn you of the above if you load it with a dead battery (specifically mentioning the game is still playable), so you would have figured it out yourself besides. If you cannot save the game, it is caused by a fault unrelated to the battery.
What are the major differences between a real and bootlegged copy of a Pokemon game?
Emerald is an annoying game to pirate, because the real cartridges have a semi-translucent green colour, as opposed to the normal grey. The front label also has a glossy sheen, with polygonal shapes glazed onto it that reflect light when you move the cartridge. If you’re missing any of that, it’s fake.
Also on the label should be a manufacturing code that indicates where the cartridge ships to. Mine ends in
AUS as I purchased it in Australia. If there’s a disparity between where you’re buying from and the region on the cartridge, it’s either fake or secondhand.
From there, obviously look for the telling signs, such as the game behaving strangely or the cartridge being really poor quality. Online guides can assist with this.
If the internal battery is dead, is there a way I can replace it safely and with relatively minor difficulty?
A search brings up several guides for how to do this — though I have no business explaining them to you, haha. The most promising one is linked here. There’s a specific model of lithium battery you need that I’m not sure the availability of.
What are common causes of unexpected save file loss or corruption? Are any of these likely to happen to my copy of the game based on what I know about its condition?
The most common cause is that the game is fake, which you should be able to detect quite easily. Otherwise, the main cause would be a failure of the flash memory, which would corrupt the data. When this happens is unpredictable, though it isn’t likely either.
Save for the odd manufacturing error or the game being fake, your game should work fine. If you’ve been careful, I don’t rate either as being very likely.
Flash memory can fail after too many write cycles or from very old age, but you’re not at a point where either of those things are a concern.