People ask how much time should be spent drilling and how much time should be spent sparring?
There is no definitive answer as the answer depends on the person and their experience but as a rule, the lower belts should always spend more time drilling than sparring. Drilling allows you to practice from positions that you may not be able to get into yet.
For example, if you are being taught mount in class but when it comes to sparring you may not be able to ever get to mount to integrate the techniques you were taught in class therefore drilling is irreplaceable as the drill should start with you in mount.
But as a higher grade don't think that you should be drilling any less as the above applies to you too. If you are one of the better guys in class you may rarely find yourself in a bad position so by drilling you put yourself in that bad position to start with.
The final word on drilling, the drills that you do should start with a compliant partner and then as soon as practicable the drills should go "live". You can practice cross choke from mount against a compliant partner for 10 years yet when you try to do it for real, when the guy underneath is really trying to escape, it's a different matter altogether. You have to be able to apply the technique under the very real pressure than you would get in sparring.
At this point drilling becomes 'isolated sparring' anyway.