I'm a fan of the Law and Order series, and all the variants, CSI, SVU, etc. Milady and I watch them at night when we're together and they are great entertainment.
While talking with some high school students last week I had the opportunity to highlight the difference between police work and the Hollywood version.
DNA results on TV are blazingly quick. On TV, you get the results that afternoon, or the next morning. In real life it takes 6 to 12 months. Months.
Drug analysis on TV is virtually instantaneous. In real life, it takes 6-8 weeks.
Fingerprint analysis is getting faster in real life. If I can get my latent into an AFIS reader, I can get the results in an hour or so. Those results will probably be that the latent I took can't be identified in the database. There are very few good fingerprints recovered from a crime scene. There are even fewer that are actually used to solve a crime.
One trick I learned as a young investigator took some planning, but I spent an evening once, with a clear piece of glass and a SIRCHIE latent print set, taking latent fingerprints of myself. When I got five good prints, I put them on a latent card, a strip that easily fits in a pocket. When I'd interview a suspect, I'd take the latent strip out of my pocket and drop it on the table in front of the suspect. Then, I wouldn't refer to it again, for any reason. If the critter asked, I'd tell the suspect to not worry about those prints, that I'd have them analysed later.
Those prints got me a lot of good confessions. When the defense attorney asked later about a set of prints that his defendant was talking about, I'd tell the attorney that there were no usable prints taken at the scene. Which was the absolute truth.
A crime lab is a valuable tool, and one that we rely on to put the icing on a criminal investigation. Crime lab results are truly useful in eliminating possible suspects from prosecution. While you're waiting for the results, you still have to do good police work. In most scenarios, the police work is completed and the case is sent to the DA long before the lab results are in hand.
Don't believe everything you see on TV.