Always make sure that your reader knows the abbreviations and acronyms used. Make sure that you define each acronym at the first use. After that, you can use the acronym throughout your document.

When my dad was a young police officer in the 1960s, one of his supervisors left him a note that he wanted all documents ASAP. He spent some time pulling together documentation on the Alcohol Safety Awareness Program (ASAP). Later he found out, that the supervisor just wanted something else "as soon as possible."

I work for a company that has lots of internal abbreviations. We have a multifamily division. I had to give an informal presentation on what I was doing as a technical writer at the local Society for Technical Communication (STC) meeting. I talked for over 20 minutes about all of my "MF" projects. I had "MF" user guides. I had "MF" training guides. I went on and on until a guy in interrupted me. He said that if I didn't like my job, I should find another one. I was puzzled until I realized what I'd been saying. I had to quickly tell them about our Multifamily division. (We also have a Business Systems department.)

When I taught at a junior college in Richmond, I'd always put the agenda on the board. I used the abbreviation for "to be announced" once. I had to define it for the class when a young man stopped me at the end of the session and announced that we "didn't do any TBA today."

These funny examples show the importance of defining your abbreviations and acronyms for your audience. Don't take it for granted that they know what you're talking about.