You may ask yourself, for some reason, “should I practice scales?”. Yes. Yes, you should.
There, that was easy to answer, wasn’t it? One reason you may find yourself asking that question is that it isn’t too hard to find click-baity YouTube videos or blog posts shrilly claiming that whatever you do, you should avoid scales (they are wrong – you should practice them). People will sometimes echo that misconception in online forums.
The people making these claims might be simply wrong or they may be deliberately misleading. Either way, please just smile, nod, and carry on practicing scales.
Technique, which includes scales, is the foundation of your ability to operate your instrument fluently. Strong technique gives you the freedom to play what your creative mind imagines. Too much technical skill is never a problem. You don’t have to use all of it all of the time. You only need as much technique in any situation as is required. However, there is an important difference between not being able to play something because of weak technique (or lack of knowledge) and making a deliberate, artistic choice to play in a more simple way. One is an excuse, the other is a creative choice.
Much of the music you play will be based on scales. Chords and arpeggios come from scales, and scales are like extended chords. Scales and chords are linked inextricably and practicing both will help you achieve fluency. Also, the simple muscle movements and patterns in scales help develop and maintain your strength and dexterity. Yes, you should practice scales.
One reason for people taking an anti-scales stance in jazz is as a reaction against a prominent approach to jazz education, typified by the famous Jamey Aebersold books, which teaches chord-scale relationships as a way into improvising for new and less-experienced players. The difficulty with such an approach is that, without guidance from a good teacher, it is easily misunderstood. Misused, it can lead to students playing in a halting, distinctly “unjazz”-sounding way. Skipping clumsily from scale-to-scale is not the way and usually sounds disappointing.
Another reason for the scale-hate may be that it is relatively common in the jazz world to misunderstand the difference between performance and pedagogy (teaching and learning). We do exercises as part of learning and developing skills that may not sound like the finished-product on “the bandstand”. But students’ exercises aren’t all meant to sound like a performance because they are for training. Imagine someone telling sprinters not to practice starts because “that’s not how you race, man. You need to run the whole thing”. Telling people not to practice scales is just as silly.
You ask: “should I practice scales?”. Yes. Yes, you should practice scales.