You can apply now if you want to. They used to allow 6 months before expiry but they have changed it to 9 now. Getting it takes approximately 151 days according to the current times which is about 5 months.
A renewal card might be mailed to your address but there is also a chance they will ask you to pick it up at a local CIC office.
If you are currently living outside Canada, the chances of having to pick up your card in person are increased by quite a lot.
If do not meet the RO (residency obligations) of 730 days and ask for H&C grounds or your time in Canada can not easily be verified, say you have not been working or studying, are very close to the 730, have many trips outside Canada etc., it is possible that they will send your application to local office to further investigation and that can really delay it.
