You open your Ledger app to receive, and the address it shows is not the same one as last time. For a lot of people this is a small moment of panic — did the old address stop working, or are the funds lost? Neither. A Ledger address that looks different each time is completely normal, and once you understand why, it stops being worrying at all. The key is the difference between an account and an address.
A changing address is normal — why it looks different
First, the reassurance: nothing is wrong. Most modern wallets, the Ledger app included, hand you a fresh address whenever you go to receive. That is by design, not a glitch. It does not split your funds, lose anything, or create separate wallets — it simply gives you a new destination each time. So seeing a different string than the one you used before is exactly what is supposed to happen, and it is not a reason to worry.

The difference between an account and an address
The clearest way to think about it: an account is your wallet for a particular coin — your Bitcoin account, your Ethereum account, and so on. An address is a single destination within that account, and one account can have many of them, all belonging to you and all feeding into the same balance. A new address is not a new wallet; it is just another door into the same room. For how these are generated, see private keys and the recovery phrase.
Why a fresh address appears each time you receive
The reason wallets rotate addresses is privacy. Reusing a single address makes it easier for outsiders to tie your activity together; a new address each time makes that much harder. Importantly, every address you have ever been given still works and still belongs to the same account — funds sent to an old one are still yours and appear in the same balance. So nothing is lost when the address changes; it is simply a privacy feature working exactly as intended.
What to do in practice
Day to day, just use whatever address the app shows when you receive, and confirm it on the device screen as usual. You do not need to track your old addresses or worry when a new one appears — it is the same account underneath, with the same total balance. If the bigger picture of how the device manages all this is still new to you, what a Ledger hardware wallet is ties it together.