If you only want to play for one hour a week then youve chosen the wrong instrument. The trumpet is the WORST instrument in the world to do part time. Not to mention that one hour a week will do nothing for your endurance or your technical skills.
I will go even one step further and say that if you want to even be in the league of a professional player then one hour a day won't do much for you either. I was at this point years ago before I decided to commit myself to the trumpet and make the nessasary sacrafices that pro playing demands.
I recomend at least 2 hours of serious practise a day to maintain yourself if you are a serious player. You should devote one hour a day to study and play your theorie and the other hour to have fun with what youve learned.
Personally the above is what I do during the week and on weekends I play about 5 hours a night. You also must remember that how long you practise will reflect on what you can do the next day. Additionally remember also that the embouchure is a muscle and must be worked much like a body builder works his muscles in order to acheive useable results.
I would love to take tonight off because I'm tired, but I have to put my 2 hours a day minimum in so that I can maintain my lips.
I dont mean to sound harsh, but the trumpet demands commitment. Good luck on your endeavor!
PS If you want to be a trumpet player with out the sacrafice of playing daily then you may want to check out a 'Digital Trumpet' at this site. They claim on the site that theres no need to exercise your chops playing this instrument. Go to
http://www.morrisondigitaltrumpet.com/
Rick AKA Trumpet Man