How does the trainer level affect powering up Pokemon?

As you level up your trainer level by catching pokemon, hatching eggs, stopping at pokestops, etc. You will find out that this will also increase your max CP for your pokemon. For example I was level 12 and my max CP for my pidgeot was 744, now I am level 13 I can boost him to the next MAX CP that I have obtained.

TIP: However this can be bad because you will use more resources than needed (seeing as the more you power up the more it costs every boost). You might want to evolve the pokemon with the highest CP and just keep replacing the pokemon until a respectable MAX CP can be obtained and you have higher CP pokemon to catch(so you boost while the cost is low on a higher level CP).