I read a post recently in another journal about short-lived magic. The poster was understandably a bit frustrated and even perhaps a little disillusioned because a desired result hadn't lasted as long as s/he wanted it to. Admirably enough the poster pointed to the simple fact that examining the process of how the magic worked could indicate a lot about why the results weren't as long lasting as hoped for. I've always felt that magic is a process and not a result. While results are important as indicators of the process working, they nonetheless are not the process of magic. I see a result as a sign. It indicates what direction you are going in and can indicate if the process is or isn't working. It may even indicate what specifically is not working in the process, though usually this requires some digging on the part of the magician. That digging can involve looking at what's going on in your internal landscape, or it can involve testing each part of your process and determining if you left something out of it that could be essential to it.
I've certainly had my share of magical workings that didn't quite result in what I wanted, or where it seemed like I was successful only to realize later that my success wasn't quite what I wanted. Magic is a process of trial and error, of experimenting to determine what works, while also learning what doesn't work. Mistakes are made, inevitably. What we do with those with mistakes determines if they become failures or if we learn from them.
Magic treated as a process allows one to examine it as an iterative cycle, with improvements occuring every cycle as more is learned about how to refine the process. The magician is part of the process and so inevitably the work of improvement necessarily changes the magician so that s/he becomes the person s/he wants to be. Like any process, the changes are rarely instanteous or dramatic, but they are important and tend to have a long lasting effect on the magician. Magic as a process isn't nearly as glamorous as when results are focused on, but while the results may not always be flashy, the process itself continues to hold true even as it is refined and tested by the magician.