How many days a week should you workout to make gains? Is there an optimal number of workouts you should be doing? As with a lot of things in regards to training there is no 1 answer.
The first thing to consider is how much time do you have to dedicate to training. When I meet a new client the time they have available will dictate what type of programme they will follow. There is no point giving someone who has 3 days per week available to train a body part split programme as they would need at least 5 days a week to do the complete programme.
Another important factor to consider is how long does it take you to recover from training sessions. The type of sessions you are doing and training age (experience and skill level) can play a massive factor here. Someone who lifts heavier weights such as a powerlifter may need more rest than someone who does lighter to moderate loads. Beginners may also find they need more recovery. The same could be said for someone who does more steady state cardio as opposed to interval training which will require more recovery time. Lifestyle can also play a part here. Someone who doesn't get a lot of sleep or their diet isn't quite right may also find they need longer to recover.
In my opinion the points above shouldn't be dictated by your goals. For example you shouldn't think I want to improve my squat so I need to go to the gym and squat 3-4 times per week. While everyone is different I have made lots of improvement on my squats by simply squatting 2 times per week whilst I train 4 days per week. That fits in with my schedule and allows me to be consistent which as always is the most important thing. We also cannot discount the importance of diet if your goals are more body composition based. I’d much rather see a client spend 3 times a week in the gym rather than 4-5 if they have to compromise their diet to do so.
Unless you compete or you are on a really restrictive diet to drop fat quickly most people do not need to train more than 3-4 times a week to make good progress. Do not ever fall into the mistake of thinking that you need to go more often to make progress if it’s counter productive. 3 good sessions are better than 5 half arsed sessions. If you follow a good programme that is structured and specific to you, it should be able to fit in the above points while allowing you to head towards your goal.