Pokemon-go – New Pokemon bonus with Lucky Egg

You are eligible to claim the "Defender Bonus":

• Once every 21 hours
• If you have at least 1 Pokémon in a gym at the time.

One you have claimed your bonus, you will need to wait 21 hours before claiming it again.

You can gain additional bonuses if you have 1 Pokémon in other gyms as well (you can assign 1 Pokémon to multiple gyms, but you can't have multiple Pokémon in the same gym), which will increase your reward. However, this still is only available once every 21 hours, from the time you last collected your "Defender Bonus".

• Adding Pokémon to new gyms does not reset the clock
• Losing a Gym does not reset the clock
• Changing the time on your phone does not reset the clock^{[citation needed]}, as all user information is stored on the servers.

Therefore, the only "strategy" I can suggest is to

1. Maintain your gym, so you can maintain your defender bonus
2. After the countdown ends, add Pokémon to as many gyms as you can, then claim your bonus, before you lose the gym.

This has changed, as of June 22, 2017

The Old Defender bonus was replaced with an automatic reward system, granting a player 1 coin/10 minutes a Pokémon was active in a gym (raids will place a gym "on hold", and Pokémon will not claim coins in this period, or lose health over time); to a maximum of 50 coins per day, that resets at midnight, and is automatically claimed when Pokémon are kicked out a gym.

This means that if you have 1 Pokémon in a gym for 8 hours and 20 minutes (500 minutes) you will gain the max 50 coins. Any other Pokémon that are in gyms in the same 24-hr period that you claimed this reward will no longer reward you with coins.

Don't worry about saving new catch bonuses

Trying to control your catch bonuses during a lucky egg effect is not an optimal use of the XP bonus. You will earn much more rep evolving as many Pokemon as you can instead of catching new ones.

The evolve animation is shorter than the animations for the Pokemon appearing, knocking your pokeballs away or dodging, then shaking until captured. Incense and lures can't get rid of the animation delays, nor are they 100% guaranteed to keep supplying you with new Pokemon as fast as you can catch them.

Instead, you can hold off on using the lucky egg until you have more than enough candies to evolve Pokemon constantly (or as fast as the evolve animation allows you, anyway) for the entire duration of the effect.

As a new player interested in gaining XP optimally, you may also want to take a look at the answers to What's the best strategy for early play in Pokemon-Go?

^{I realized later that OP was the one who asked the best strategy question, but it has relevance for any other readers so I'll leave it in all the same.}