ninagruenewald Hey, Nina!
I'm not going to write a bullet list of all the differences between agencies and direct clients because you just need to google "agencies vs direct clients" to find tons of those.
Personally, I haven't targeted direct clients so far and I am working mostly with agencies.
In order to find out whether your services suit a particular client or agency, as a best practice, you should go through the information available on the Internet, such as on their website and on social media (their profiles, posts, and interactions). Sure, if a client manufactures screws and you have tons of expertise in screws, chances are you will be competent for the job. The question is, does the client need your translations? Do they sell in your native country? If yes, do they have translators already? There are so many aspects to consider... all in all, what you should do is "study" your target persona, decide what they do, in which sector they operate, what they need, whom they want to reach, and then find the client with the profile most similar to the one you've outlined.
As to security, I think clients may disappear from one day to another, but so can agencies. The best strategy is to differentiate your income, i.e. work with several clients or agencies so that, should any of those drop you at any moment, you'll still have other sources of income!
