i spent 5 months for my first one. some go longer some go shorter. i only plan on 2 a year so i may go between 4-8 months for training for a meet. i have friends that have already done 3 meets this year and already have the next 2 in their plan.
at first i would say the experience is worth a shorter prep time in months. once you get more advanced gaining even a few lbs may take many months and then meets may only happen 2-3 times a year. just remember it is a skill. so maybe some meets for you are practice meets to grease the groove and not world record smashing events.