You should restore your @wallet in the following situations: - You lost access to your wallet (you forgot its password, your wallet file is corrupted or your device stopped working/is lost).- You want to create a copy of your wallet on another device.
A valid Monero mnemonic seed is a phrase with 13, 14, or 25 random words (multiple languages are supported). Your mnemonic seed has all the information needed to restore your wallet.
Most Monero wallets ask the user to write down a mnemonic seed on a paper backup when a wallet is being created. So it's up to you to remember where and how you stored your mnemonic seed.
Alternatively, if you still have access to the wallet being restored, you can usually find your mnemonic seed in a menu with some name like `Seed`, `Keys`, `Secrets`, or `Master Private Key`.
The walletrestore height is a setting that tells your wallet software at which block height it should start scanning the blockchain looking for transactions. Ideally it should be the number of the block which included the first incoming transaction to your wallet.