This is another common interview question (as is “What are Your Strengths?” discussed in a previous post.
The worst answer? “I don’t have any.” Nobody will believe that, and if you believe it, it shows both arrogance and a lack of self-awareness. Nobody, as they say, is perfect.
Another poor answer is to highlight a core part of the job as a weakness. If this is true, why apply for the job?
The better answer is to find a previous minor weakness that you have already addressed. For older people, that might be a fear of technology, which they cured by doing a course, which in turn led them to running a blog on their particular hobby. That kind of answer also nicely deals with any unexpressed concerns over technology.
Another approach is to pick a weakness that can also be a strength. “I always want to dot all the i’s and cross all the t’s” can indeed be a weakness. It might also illustrate attention to detail and the fact that you are a finisher of projects.
As always, you need to be honest.