It might be a good idea to keep it at least one year under the limit that registrars set. If you ever want to move to a different registrar, you usually have to

It might be a good idea to keep it at least one year under the limit that registrars set. If you ever want to move to a different registrar, you usually have to add (and pay for) an additional year, and you can't do that if you're at the max (often 10). I recommend 9 years.