This is a very common question for new user .As with everything in the world of hair replacement (or so it would seem), there is never a "cut and dry" answer. The life of your system- no matter what base you use, will depend on many different factors, such as how you care for the system, how you wear/attach the system, etc. As you can see when you view many of our different lace bases, it would be unusual for a full lace base to last longer than about 4 months or so. However, I do want to note that with proper and diligent care, lace systems can last much longer. Lace and poly are two very different materials. Lace will tend to provide a much more natural appearance, typically be more comfortable (breathable), and if you plan to use Hollywood lace, the material will be very soft and light. Poly, however, will provide you far more durability, and can also handle a much heavier density than most lace systems can. If a visible front hair line area isn't important to you, then poly can look incredibly natural. When it comes to making choices about base materials, you may want to ask yourself, "is it more important for me to have a durable base, or a natural looking base