I don't bother introducing "in" colors and lots of trends, nor do I pay any attention to what is season approprate (i.e. no black pants in summer). If I did, I would go entirely crazy. I feel like no matter how "finished" I think I am with my wardrobe, there's always something missing, even without paying attention to trends.
The good thing about a shopping ban is that it helps you understand what's missing from your wardrobe, and what should have priority. This shopping ban has put dresses high on my list of priorities. Every year of my life until now, I have continued to wear jeans all year long--even on the most blistering hot days of summer, so I thought my many pairs of jeans, in all different washes and cuts, meant that my wardrobe is fine the way it is. But now I think dresses would be a lot more comfortable, and a lot easier to wear while still looking great. On days when I don't want to wear dresses, I would prefer some clams or walk shorts, which are also lacking. So my shopping ban has lead me to conclude that I have to get rid of some of my jeans and replace them with dresses and cropped pants. If I didn't go on a shopping ban, I would probably have bought a lot of things I don't really need before realizing that I do need dresses and crops.
All of this means that I will give in easily to temptation, but never on frivolous things. One way or another, I'm going to get that Free People dress. If anything, it will just make me even more determined to finally find a job (still no luck on that end). I also feel like that dress is something I SHOULD be able to afford. It's pricey but not that extravagant, like a DVF dress, so that adds to my frustration and temptation. It really is the exact kind of dress I have been waiting for, so if I pass on it I know I will regret it.
Year to year, I don't find I need to update my wardrobe to incorporate styles and trends that are of the moment. I think what you want to do is very possible, and probably the most practical thing to do Ana. Falling all over every single trend is a PITA, impractical, and probably not even a good idea from a style standpoint. After all, not every trend is going to flatter you.