A lot of preparation means that a significant amount of effort, time and planning has been put into something to ensure it is well-prepared or ready for an event.
If you are leaving the military after several tours or upon retirement, do recognize this transition will take lots of preparation and time. (job-hunt.org)
The arrival of the newborn baby needs lots of preparations from buying toys to having bassinet sheets, blankets, and for some, video baby monitors even. (pearltrees.com)