I have always looked at being Spirit filled like this....
We ask to be filled with a sincere heart....God fills us, and every time we pour out to others, our glass is refilled. Complete dependence on our Father as to being filled once more.
All glasses (vessels) are viewed as equal in God's eyes as far as He is willing to fill anyone who asks in His name, but not all vessels will yield to God to allow all the gifts to flow to them. God could lay a huge missionary mission in my lap today that needed to be lead, but if I'm not ready for that gift, because I have not purged myself of the things that pollute my vessel of water, then my vessel is tainted and not pure in my outpouring to others.
Otherwise, a vessel that allows God to purge them of impurities will be a vessel of overflowing blessings and will work in the gifts that were intend for them.