A fundamental principle of choosing a resource for a class should normally be skilled selection and grading.
This involves choosing material which approximates to the current level of a class and then takes them a step further. With a text, for example, you do not want to overload the students with too much new vocabulary or unfamiliar grammar. Some theorists would favour a "finely tuned" selection and grading whereby you very carefully design or choose a resource to include previously practised material plus just a little more. Others would favour "rough-tuning", arguing that you do not need to worry too much about focusing on the form and that interesting content of roughly the right level should be sufficient.
Teachers who favour more naturalistic approaches (e.g. TPRS or CLIL) place less emphasis on fine-tuning, whilst making sure, in general, that they limit the range of vocabulary and grammar they present and practise.
Most teachers in a high school context stick with a more finely-tuned approach, at least in the early stages, basing their selection and grading on a grammatical progression with topics bolted on.
My own preference in early stages is for a fine-tuning approach. This the one adopted by traditional textbooks going back many years and features a grammatical syllabus with just a small amount of new material being introduced at each level, with plenty of revision built in. The Tricolore course does this pretty well for more able learners. A good principle to keep in mind is that you do not want to present learners with lots of new vocabulary whilst you are also teaching a new point of grammar. Gianfranco Conti, in his excellent blog, refers to this in Point 2 here. In essence you shouldn't overload students with too much new material at once.
One clear disadvantage of fine-tuning, with its focus on form, is that it restricts the topics you can cover so you end up avoiding potentially interesting subject matter. The familiar challenge is to try and marry smart selection and grading with interesting content. It's not easy.
At a more advanced level, once the basics of syntax, vocabulary and morphology have been grasped and partly internalised, I would be less fussy about fine-tuning. By this stage my own inclination is to assume that lots of comprehensible input will generally do the job along with however much controlled practice seems necessary with the group in front of you.
There is, alas, despite what some claim, little convincing research which lends support to either of these approaches and in practice I would think most teachers in the school setting use a mixture of fine and rough-tuning.
What I consider poor practice is choosing a resource which is clearly much too easy or much too hard for a group. This is a potential danger of wanting to use, at all cost, authentic resources. The latter have not been written with learners in mind so are very unlikely to be finely tuned and may not even be roughly tuned. The current requirement to include literary texts in GCSE teaching causes a real issue with selection and grading. Hardly any material from a novel or play will be suitable so teachers will be wise to avoid these and make use of well-chosen songs or poems. Feature films are also an issue and can only really be justified at lower levels for their cultural value with most classes.
I have written a little more on this here.