I bought some bitcoin on Cobinhood. Can I send them now to the desktop wallet of bitcoin.org, and leave it there for 5 years or longer, without caring about it in this timeframe? Or is it neccessary to update the wallet from time to time? What happens when Litghting-Network or a fork is coming, do we have to update something?
As long as you keep private keys, passwords, and seeds saved you wouldn't even need to keep your wallet installed on your PC. You can leave your coins lying around for however long you want since they are stored online on the blockchain rather than in your hard drive. If you do have the wallet installed then updating it really isn't mandatory if you aren't even going to touch for for those five years. If you do want the forked coins you will probably want to install the wallets for the coins being forked. Just make sure to keep the private key, password, and seed backed up somewhere safe (If lost you'll be out of luck and lose access to your coins.) You should be golden then if I'm correct.