With the advent of the internet there are so many more resources for information.  Information about learning the guitar, buying guitars and fixing instruments are more abundant than ever before.  Due to the nature of the internet, everyone can post videos, blogs and forum comments, good and bad.  There is no internet watchdog that checks these sources for accuracy and quality, so please keep that in mind when searching for information.  Of course, there are many, many great sources out there and usually you can get a feel for how good they are by the comments, quality and general attitude of the posters.  I am always interested in learning and seeing how others do things and in doing so, I've learned new approaches, techniques and ideas that have helped me progress in my field.  I've also seen a lot of posts, videos and such that were utter garbage and quite a few that were half right/half wrong.

I'm all for learning how to do new things, including guitar repair, maintainence and playing and think everyone could benefit from knowing more.  Much like being a driver and knowing how to change a tire or your oil is a good thing, so are some guitar related tasks.  Here's a couple of tips for Doing It Yourself, when to and when not to:

1. Check the quality of your source.  If the person comes across as a rude jerk, avoid.  Anyone that doesn't take the care to present themselves in a well mannered, professional way is not someone I'd take seriously.  The good guys tend to take a "this is how I do it" approach rathering than a "this is the only way to do it and other ways suck" approach.

2. Know what your strengths and weaknesses are.  Are you a detailed oriented person or pretty casual towards your gear?  Wiring in an input jack is relatively easy and hard to mess up (though I still see them).  Detailed fret work is not something you can just take a whack at.

3. A botched DIY repair will cost you more to fix than the original problem.  

4. Do you truly understand the problem?  A very common mistake I see on guitar forums is people giving advice on repairs without knowing the exact problem.  For example, a fret buzz can have several reasons it is happening, even multiple reasons at once.  The advice of 'adjust your neck' without knowing what is the true problem can just make it worse or at the very least add one more thing that needs fixed after truly fixing the original problem.

5. Take your time, plan your moves.  Being rushed is never good.  Being in the middle of a repair and forgetting a step can be terrible.  You don't want to be in a position where glue is applied and drying and you forgot a needed part.

6.  Multiple sources, especially for the more critical jobs.  A video, forum post, book, do some research on multiple opinions and approaches.

7. Know when to stop.  Things not going right?  Something isn't lining up?  Stop.  Better to take a repair to a luthier half finished than badly finished.

8. Practice on cheap gear.

9. Quality parts make most repairs easier.

10. The proper tools exist for a reason.  Us repair guys and gals invest a lot in our tools, we even modify and build our own when needed and all of us will tell you instances when the right tool made all the difference.  Gorilla Glue for a bridge reglue is not the right tool.  Peghead reamers exist for a very good reason.  Scotch tape isn't just as good as shrink wrap.