A bit less, since you have to worry about an attacker storing anything you do now for future attacks.
But if you only want any given secret to stay save for 20 years, you can still use 4096 bit RSA for another 17 years. Which sounds like a good tradeoff: enough of time for better algorithms to get established, but little risk of a breach you will care about.
But if you only want any given secret to stay save for 20 years, you can still use 4096 bit RSA for another 17 years. Which sounds like a good tradeoff: enough of time for better algorithms to get established, but little risk of a breach you will care about.