I don't not see much risk in saving your bitcoins in a wallet for longer term unless there is a hacker attack. But try not to keep the bitcoins in an online wallet like coinbase or blockchain. Their policies keep changing and you may to be aware of such policy change if you are planning to keep your bitcoins for longer term. Instead try to use offline wallet like Electrum. Just download and install the wallet. You don't need to download the entire blockchain with electrum wallet as it is connected to a central server where blockchain is being downloaded. So whenever you open that wallet, it connects to the blockchain and whenever you close it, it gets disconnected from the online server. It's safe and you will have access to your private key as well. My recommendation is Electrum wallet.