Everyone is different and depending on where you are with your workout (person who has lifted for 5 years straight vs. someone new) you will be better off with certain routines.
One of the things you didn't mention is what your goals are. Without this you will not get a great answer.
Are you lifting because you want to be better at sports? If so this workout is a bit static and I would include other lifts that move the weight symmetry around plus plyometrics.
Are you lifting to get stronger? Then this workout is a bit mundane and isn't focused enough on intensity. You would need to probably need to increase the weight and decrease reps for a few sets. You would also probably need to do complimentary lifts.
Are you lifting to maintain while getting a little stronger? Then your workout probably suffices. Here you should be focused on doing the lifts correctly since your margin for improvement is smaller. When you lift and get sore is the soreness focused on the correct area - for instance squats should make you sore from where your butt meets the back of your leg to the front of your hamstring. If you are getting sore in your back or hips there is a good chance you are doing the lifts wrong or a good chance you aren't doing complimentary lifts and seeing weakness in other parts.
There just isn't a perfect answer. Your workout seems "quick" but with 100% intensity and correct form it is more than adequate for a person 4 months in. If you are getting gains, can manage the pain/soreness, your body generally feels healthy, and you are happy doing it, continue until you start seeing yourself plateau.
Depending on age doing this twice a week is doable but at some point you may need to cut back to once times more lifting or possibly just take intervals off of the second day. But it is nice to hear someone 4 months in doing legs twice a week. Your body will grow much quicker with a stronger core.
So the answer is - it is enough if you are getting gains. If you aren't you may need to move on to a structured routine like stronglifts or SS. But if your weight is going up at a good rate, keep going. If it isn't ask yourself, is it my routine or is it my intensity. If you think it is your routine, post your exact routine with weight amounts over a two month period and many people can off advice and other things you could do.