One giant heap...
There are two kinds of people. Those running towards their past, and those running away from it. The former group will often find that the past has little interest in them, while those who claim to be done with their past will usually find that it's not done with them.
It's true that our present is enormously influenced by things that have happened before. Memory and experience are good things when it comes to remembering how to open a door or land a lunar module. But when memory and experience cloud your view of what's in front of you, i.e. the present, things get very limited and/or very interesting.
Zen masters listen up... By now we've all experienced the violence of trying to be in the present, the brutalness with which our sprawling and all-consuming internal life can arrive limp and stillborn in the cold, chaotic light of day. Environmental conditions inside of the skull and the heart are very different from those on the outside. These are perhaps the most important bridges a human can learn to cross.
Knowing how to balance a selective past with a fluid present, knowing how to unscrew the emotional lenses from our here and now perceptions, knowing how to access experience without the dread of reliving past failures or pain, knowing how to get the pancakes out of our space suits, these are the skills you'll want to be honing homeslice.