I did mine my self but i would not recomend this as a task for a total beginer, best fuck up a couple of cheep watches and once you can break them work you way up to breaking expencice ones, at that point you may have gained the experience to do the date wheel swap, and that is acualy the easy part, given a movement out of a case andf a new date wheel it is a 2 min job, now getting the hands back one and the whole thing re cased with out scratching the hands ( like i did) well that is another story.
I have a draw full of experience in bits from cheep watches.