It's important to work out every day, but spending too much time in the gym won't help you lose weight or build muscle.
Depending on what you're trying to achieve will determine the minimum or maximum amount of time you should spend on your sessions, and in general, what the week's duration adds up to. I like to think of motivation as my goals and what fits into my schedule. Most of us have full-time jobs, families, kids, and other things to consider. It's important to make sure these all fit when planning your training. I'm going to highlight some key points for you broadly as they can help you and many others looking for answers to this question.
Two key considerations for achieving your fat loss and muscle building goals.
Will you train before work, at lunch, or after work?
Deciding whether to train in the morning, at lunch, or in the afternoon is very important based on your life plan, and the demands of your job. You have to find a time frame, and a place in your day where you can continue your workout - without distractions and with complete focus. If you don't take this into account, your training sessions won't be effective because phone calls, e-mails and messages will certainly spoil these. Then give it a go within the training window and absolutely nothing will happen. Perhaps another factor is that your workouts are taking too long because you've been busy answering phone calls and responding to emails while you're working out. When it's time to work out, multi-tasking won't earn you any loss of gaining muscle or fat! Keep this in mind when choosing your special window. The best advice I can give is to train in the morning. Not an early riser, then if this is the only way you can have the peace, quiet and serenity of a limited space to continue your training - get over the early morning thing. The most important thing is that you put in the time, effort and commitment to your goals - no matter what time it is.
What kind of training will you receive?
If you're training for a marathon, Iron Man, or something like that, trying to build muscle or gain fat, then all of that is going to have a big impact on the amount of time it takes to achieve that goal. Often, these workouts require a lot of time invested in their endeavors. They want to win, or best, beat their personal best from their last marathon. Sometimes training twice a day is required for optimal performance. I can't comment on program training, although I can definitely offer some solid scheduling advice when it comes to weightlifting and cardio;
1. If you're losing fat through cardio, you should embrace HIIT, which is a high-intensity, all-out workout for a short period of time, followed by active recovery. The full duration of this process is usually between 20-30 minutes. If you can do more than that, you're either really fit or you're not working at your absolute maximum capacity. If that's the case, your body needs to stop at around 30 minutes.
2. For strength training you need at least an hour, maybe a little more for this one. The reason for this is that after we finish a set, the time needed for recovery should be between 1.20 - 2.30 minutes. Strength training requires us to lift to the maximum of our capacity, doing at least 3-6 reps. By the time we have completed all of our recovery, an hour has passed. This doesn't mean you are working out the entire time, you are lifting weights to give your body enough time to recover. It's a way to build strength, and that's what powerlifters do.
3. If you are training for obesity, your workouts should last between 40 minutes and an hour. Anything more than that will be detrimental. You need to allow a very small recovery window and use moderate weights. Movements should be between 8-12.
I am assuming that you are training for the above mentioned, so you can see that each stage of the workout requires a different amount of movement. Each week should be different, depending on what you are doing. Don't do the same exercises every day and every week. Change often because your body is susceptible to workout adaptation and you will experience the dreaded plateau.
Before I close, I want to mention the importance of diet. The first and most important sign of our body composition and health outcomes is what we choose to put in our mouths every day. Make your choices wisely, because no amount of exercise will help you with that.