So recently the shutter on my D50 has been "sticking". It is approximately 5 years old and has probably 15K shots through it. Issue doesn't occur on all shots, or even consecutive shots, it crops up randomly everytime I take more than a couple of pictures. What will happen is after I depress the shutter release it will open, but not close until I depress the shutter release again. Does that sound like a failing shutter? Or just a grimy camera that needs to be cleaned? At this point its probably not cost effective to dump more than a few bucks into that camera since I'm looking to upgrade before the end of the year, but hoping to make it last until then.