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. Full definition
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)