Flynn: it's my first NG base from TL. John said me that you can keep it until 4 months, and in my opinion I think 3 months without problem, I can't confirm it now coz it's my first TL ng. A thing that I didn't say on this thread is that I am very impressed by the solidity of the base. I badly glued it so I had to peel off it, and at this moment I was thinking: wow it is so solid! I say that because when I was a saloon client's I was a thin skin user.. but their thin skin was thicker than TL NG, and was very very fragile. So my conclusion is that TL sells an invisible thin skin of 0,03mm more solid than the old school thin skin (surely a 0.05mm or 0.06mm maybe more!) that I used in the saloon where I was client. Honestly I am a very demanding wearer, really demanding. The NG that John sold me is just impressive! In term of invisibility and in term of hair quality. Maybe John won't be agree with me but I think that the hairs of this ng base are better than the hairs of the stock lace units... I speak only about stock unit coz I buy only that for the moment.