You look at your rack of letters before your turn at Scrabble, and you don't see a good opportunity to form words on the board. When can you exchange tiles in Scrabble?
The Rules for Tile Exchange in Scrabble
You may swap one to seven tiles instead of playing a word on your turn. You can only do this if at least seven tiles are still in the bag. If you are near the end of the game and six or fewer tiles remain, you can't exchange your tiles.
When you exchange your tiles, you are passing on forming a word in that round. You will have to wait until your next turn to place a word or to exchange your tiles again.
How to Exchange Tiles in Scrabble
Exchanging tiles is a three-step process. First, remove the tiles you're going to turn in from your rack and place them face down on the table. Then draw an equal number of tiles from the bag and place them on your rack. Finally, put the face-down tiles back into the bag.
You don't want to reveal the tiles you are exchanging to your opponents. You have a slight advantage in now knowing some of the letters remaining in the bag, and you don't want to let them in on it. Once you have exchanged the tiles, you are forfeiting forming a word on that turn. You will have a zero score for that turn.
Passing Instead of Swapping Tiles
Rather than exchange tiles, you can also pass your turn and take a zero score. This is your only option if there are six or fewer tiles remaining in the bag. If all of the players pass twice in succession, the game ends.
When should you exchange tiles?
It is usually a better move to make any possible play than to exchange tiles. If all you can form is a two-point score by placing a single letter, it's still worth more than zero for that turn. To be able to make short words with your letters, consider using vowel-only two and three-letter words, two-letter words, words with Q and no U, and Scrabble words with no vowels.
There are times when your only move would give your opponent a chance to use a triple-word score or triple-letter score. In that case, it may be better to exchange tiles or pass.
It is interesting to note that tournament players exchange tiles less often than casual players. In part, this is because they know more allowed Scrabble words, so they see more opportunities to form them on the board each turn. They see how to add on to current words and build towards high-point plays.
They also look for the chance to form a bingo (using all seven letters on their rack) in the next turn, especially with opportunities to add suffixes such as -ing or to make plurals. This is where it pays to know official Scrabble words and how to build them.