Power Creep
A permanently purchased item in the game becomes less valuable over time.
Power creep is a term used to describe a situation where an item in a game depreciates in value over time. The main way this happens is via new content being added to the game that make the old content less valuable.
The idea is that you may have earned or paid for a powerful item or upgrade in the game. It may have been great for awhile, but new better items are available or the power level of the opponents has increased to the point where that original item is no longer useful. The money and time that you previously spent to earn that item is now worthless and you must spend more money and time on the new more powerful item to have the same benefit that you had before.
If games do this often, it encourages players to keep spending money to stay competitive. If done incorrectly by the game developer, it also has the effect of making the game boring for new players who start with the new powerful items which are overpowered against the opponents found in the beginning of the game. The original game can become unbalanced if too many updates are made that keep adding more and more powerful items.
The idea is that you may have earned or paid for a powerful item or upgrade in the game. It may have been great for awhile, but new better items are available or the power level of the opponents has increased to the point where that original item is no longer useful. The money and time that you previously spent to earn that item is now worthless and you must spend more money and time on the new more powerful item to have the same benefit that you had before.
If games do this often, it encourages players to keep spending money to stay competitive. If done incorrectly by the game developer, it also has the effect of making the game boring for new players who start with the new powerful items which are overpowered against the opponents found in the beginning of the game. The original game can become unbalanced if too many updates are made that keep adding more and more powerful items.
Examples
Egg, Inc."The cost of upgrades purchased with golden eggs increases each time you buy them"
Dead by Daylight Mobile"All characters come with abilities ("perks") that come with powerful strengths that are usually changed after several months to then be weak or useless completely, so the player will have to either buy the newest character released or never use the purchased perks ever again once nerfed."
The Battle Cats"THe cats can be power crept pretty hard, but to PONOS' credit they tend to go back to underpowered cats and attempt to buff them with things like talents"
WWE Champions 2019"Ever changing meta make things useless within months, even weeks"
The Walking Dead: Survivors"You get 5 times the items later in the game for the same amount of money you spent at the beginning, but you need 20 times more the same item to get the same progression"
Life Makeover"Clothes obtained in limited events have stats that get increasingly higher as the game goes on"
Limbus Company"some of the older characters and mechanics you can get from the gacha are much worse than others, typically because they're older"
Last Fortress"Can spend a huge amount of money but if you don’t keep spending you fall behind"
Dice Dreams - Roll the Dice, Become the Dice King"Pretty much everything you purchase is a token of some kind, so you use them up. Sometimes these tokens are for limited time events and the tokens expire when the event ends."
My Singing Monsters"As you progress and level monsters, the amount of food required to get to the next level increases sharply, making it very expensive to continue."