Stacking buffs/procs/cooldowns is mathematically always better than chaining them.
Pretty much this.
Some math(values are made up):
60k damage over 60 seconds(1k DPS), You have 2 cooldowns that both increase your DPS by 10% for 30 seconds.
Using them seperately: 1.1*30k+1.1*30k = 66k Damage
Using them together: 1.1*1.1*30k+30k = 66.3k Damage
You want to stack as much trinket procs/potion/lust/CDs together as possible to get the maximum DPS gain, you can see this at the start of any fight, you have all trinket procs, possible Engi gloves, self CDs and maybe Lust -> Massive Burst DPS