Back and forth

To do something “back and forth” means to do it in one way or one direction, and then switch to another in an alternating fashion.

When using “back and forth,” you express switching between only two options.

For example: Rideshare drivers often drive for Uber and Lyft. They flip “back and forth” between platforms: if there aren’t many Uber riders, they switch to Lyft.

This example works because there are two options. Drivers go from Uber to Lyft; then from Lyft to Uber; and back to Lyft again. They alternate between the two options.

Here are some additional examples:

• We exchanged emails back and forth to coordinate on the project. (Two people were in an email exchange.)
• The children tossed a ball back and forth in the front yard. (There were two children; they took turns throwing the ball to the other.)

“Go back and forth” on a decision means to switch your opinion frequently between two options. For example, if you’re not sure about whether you should renovate the kitchen, you can say: “I kept going back and forth on the kitchen renovation. On the one hand, it really needs updating. On the other hand, we might want to put our budget toward the roof repairs instead.”