KonTW makes a very good point, mastering the sleights is by no means the end of the practice process, in some ways it's the beginning. How much time you should put into an effect varies greatly although you could say you should never stop putting time into them. I feel that an effect is ready to begin performing publicly when I can do all the sleights involved without thinking about them, this allows my attention to be entirely on the audience. At this stage I begin thinking about refining the timing, presentation and misdirection involved based on the level of success in the performance.
To offer something a little more 'tangible', the sleights I use on a day to day basis are the double turnover/lift (the distinction between the two is very important), classic pass, gravity half pass, outjogged herman shift, top change, false shuffles and cuts, elmsley count, 4 for 4 switch, paintbrush change, one handed popover, gamblers cop. There's a fair few shifts in there which I believe is very important at a more advanced level, although many people would disagree with me and have had a great deal of success despite never having anything to do with the shift. I know many more sleights, such as a load of colour changes, I just find they don't really suit the way I perform anymore.
I selected these sleights as they serve me best for the types of routines I like to perform and are all at least angle efficient if not angle proof, meaning that while there are some slightly weak angles in some cases, these are easily covered through presentation and attention management.