Increasing load consistently, is key. However, you cannot increase load constantly, as the body plateaus after a certain amount of time. Also without, changing the other variables that contribute to the total tonnage of the squat, deadlift and bench, you would be training very boringly and sometimes, these "dark times" can last for months (Up to 12 months), where you constantly do the same thing, but see no results whatsoever.

The better way of training is to switch the variables such as tempo, rest timing, exercise selection, weight selection, deload, load. Also your  repetition ranges are extremely odd for someone hoping to build strength instead of muscle.

Personally I subscribe to the conjugate periodization methodology, and I arrange them between 4-16 week blocks depending on the length of training of my lifting clients. 4 weeks for more advanced lifters, 16 weeks maybe even up to 20 weeks for newbies. Also as the maturity changes, the load and set/rep scheme changes. I change to a lower repetition method as the lifter progresses, but usually once every fifth session, there will be a change in main exercise selection. Some recommend, 3 some 4, I prefer five.

That way the lifter will constantly see progress in the squat, bench and deadlift.