Reading in the literature on Interviewing almost everybody recommends audio recording  as well as additional video . Nevertheless I wondered how important these recordings might be especially considering that some people never learn to value a user centered design process if they find their first steps too tedious.
So: Is it worth it? (considered that you might have few time/money)
The answer is »it depends« (as usual) but I wanted to get some insight into what it depends on. Sadly I could not find the key to the rocket science building, so all you get are my experiences in several small case studies.
What I did
I did several interviews as part of three different projects. In each interview I took notes and recorded the audio. After all interviews I complemented the notes from memory as soon as possible. I filled in gaps and extended bullet points to more verbose descriptions of what was explained to me or observed. Than I transferred the information in a text file.
I listened to the recording as well and wrote all coherences, statements and explanations from the audio in a text file too (thus, no word-by-word transcript). Having my in-interview notes and my from-memory-notes and what I got by going through the recordings I could compare the results of each step.
What I found
Going though the audio made a difference – but not as big as I assumed. What was added was mostly minor details. Among the five Interviews there was one in which I relied heavily on the recordings. In one of the interviews I had seemingly conflicting statements; I was able to understand and clarify this by listening to the recordings.
The main points were already in the written notes and/or their complements.
Overall, the notes and their completions after the interview already provide a usable basis for user research, even if no audio was recorded. However, if it is possible, you should record nevertheless. It can happen that your notes are not useful (as it happened to me in one of the interviews) and you may need to review some of the recording to resolve conflicting statements or get a better understanding.