Frequency

According to much of the current literature, it appears that higher frequency leads to greater strength gains, even when volume is equated. Still, there are some general guidelines to follow where most lifters are going to make optimal progress.

Most people are going to make the most progress squatting 2-3x per week, benching 2-4x per week, and deadlifting 1-2x per week. There are many reasons why these frequency ranges work for the majority of people but the main reason is the ability to recover from the exercise. Most people can bench with a relatively high frequency because, in general, bench press allows for the quickest recovery. The bench press uses smaller muscles and typically results in a smaller absolute load on the barbell.

On the other end of the spectrum, the deadlift uses the most musculature and results in the greatest load on the barbell for most people. In most cases, the deadlift takes the longest to recover from, therefore most people can only train the deadlift 1-2x per week. Optimal squat frequency falls somewhere in the middle of bench press and deadlift frequency because it is typically easier to recover from than deadlifts, and in many cases, it is used to drive progress on the deadlift. This is typically why squat volume tends to be higher than deadlift volume in powerlifting training for the majority of individuals.

Of course, there are outliers in every direction. Some people are built in a manner that will inherently cause the squat to fatigue them greater than the deadlift. In this case, they may need to deadlift with more volume and squat with less volume. Another example of an outlier is an individual with a very large arch and small range-of-motion on the bench press. This individual may benefit from very high frequency and volume on the bench press (5-6x per week in some cases).

My recommendation is to start at the lower end of the commonly accepted guidelines for frequency (Squat 2x, Bench 2x, Deadlift 1x) and milk that for as long as you can. You may find that this frequency is optimal for you, though you may want to experiment with higher frequencies and see if that yields greater gains for you. In my own personal experience, I found that benching 1-2x per week and with relatively low volumes caused my bench press to regress. When I increased my bench frequency to 3 and eventually 4x per week, I added close to 100 pounds to my bench press in one year.

Reference this article by Greg Knuckols for a more in-depth explanation of this topic:
https://www.strongerbyscience.com/training-frequency/