Q. If I'm citing the same work for several sentences in a row, do I need to put the in-text citation after every sentence?

Multiple in-text citations to the same work over a large section of text can be visually jarring and is not entirely necessary.

The rule of thumb is to cite the very first sentence, make it clear you are still talking about the same work in your subsequent sentences (for example, "The study noted that..."), and then confirm you are still talking about the work by including another citation at the end (if this has continued for several sentences).

If you have a simple follow-on sentence in which it is still clear that you are talking about the same work, you do not need the reference in the second sentence.

If at any point you think it might not be clear in the sentence that you are still referring to the same work, include another in-text citation.

For author-date styles like APA, if you have repeated the author's name from one sentence to another, you do not need to include the year after the author's name in the second instance if it is clear you are still talking about the same work (see page 265 of the APA Publication Manual).

For example:

Auvinan et al. (2015) provided students with a visual representation of their behaviour in online environments and found that some learners started changing their behaviour as a result. It was also noted by Auvinan et al. that badges were more motivating for students that were already high achievers than for those who were struggling.

This only applies when all of the information for that series of sentences comes from the same, single source. If you are pulling from multiple sources, you'll have to cite everything each time.

Please note: this is a stylistic choice. Your lecturer may tell you they want citations for each sentence, and that's something you'll have to do. You should always check with your lecturer when you are using a "rule of thumb" rather than a convention that is written in a guide.