You may get a lot of opinions on this, but essentially calum_b is correct that while Apple used to recommend doing at least a monthly discharge/recharge cycle, they no longer recommend this (but that's not to say they recommend against it either).
You can read the entirety of what Apple says about their batteries here.
- Charge your MacBook Pro battery as it suits you. You do not need to let the battery discharge 100% (or any percent) before recharging.
- Apple have designed their lithium-ion batteries to reach 80% of their capacity quickly and then switch to a slower trickle charge to complete the other 20%.
- Ambient temperature is a big factor in determining battery health/life. Your MacBook Pro is designed to work at its best when ambient temperatures are between 16° to 22° C (62° to 72° F).
- Avoid exposing your MacBook Pro to ambient temperatures higher than 35° C (95° F)
- If you ever need to store your MacBook Pro long-term without being used, then ensure it is switched off and the battery is only half charged.
Finally, you should know that the latest research (from late 2016) has found that the biggest enemy of lithium batteries is time. Regardless of how you use your MacBook, your battery will be far less healthy in five years than it is now regardless of whether you've cycled it daily or never at all.