Overall, as a training system, resistance bands are an ingenious invention! Extremely convenient and capable of delivering impressive results, if used methodically. With the help of a door and a stool, taking advantage of different angles (standing, sitting, or lying positions) and distances of pulls (to adjust resistance), they can be transformed into a complete gym, providing a huge variety of exercises! Unfortunately, in this particular case (as other users have mentioned)... "you get what you pay for." Their material is not the most durable. At this low price, I didn't have any illusions about their durability, so I bought 2 sets. And indeed, as I had predicted: after a week of 20-minute daily use of the first set, the blue band broke first. The fortunate thing was that it broke at the end, so I tied it back on the hook - slightly shorter - without much difficulty. In the third week, the green one broke. Only this time, it broke right in the middle! At the point where it bends around the door suspension strap, which, during exercise, tightens and folds into a narrow (almost sharp) crease. In the fourth week, the blue one broke again, but this time in the exact same way as the green one. Immediately, I found a large, durable plastic ring (from a curtain) and tied it to the door suspension strap, so that the curved surface of the ring would somewhat reduce the friction of the others. However, I also noticed significant wear (it had torn almost halfway) on the strap, at the point that remains behind the door, where logically the greatest strain is applied. Of course, I should note here that gradually I pushed them hard (usually using them in sets of three or four) in strength training exercises (I wanted to rehabilitate an old shoulder injury) and extensively with the use of the door suspension strap. If I used them without folding on the strap (spread out over their entire length), I believe they would have lasted longer. However, in that case, they would require much more space to stretch and the range of angles would be limited, thus reducing the variety in performing exercises (e.g. for vertical seated pulls, a 3-meter high door would be needed to efficiently stretch the entire band!). Conclusion: For warm-up before weight exercises or for rehabilitation, where low to moderate resistance is required, I think they will not disappoint you. They are also a satisfactory solution for regular physical fitness maintenance. However, for heavier strain (muscle strengthening similar to traditional weights), I would recommend looking for something more reliable. Because everyone's exercise needs are variable and highly individualized, I think it is necessary for one to inform themselves, research extensively, and try before settling on what suits them perfectly.