This is not easy to say, two days ago I did a technical response in the bidding also encountered this problem. This I can give you a reference bar. Huawei's R4850 module, for example, according to his MTBF can calculate the module's average annual failure rate λ: failure rate λ = 1 / MTBF, Huawei R4850 module, for example: λ = 1 / 50W hours (about 57 years), λ = 0.0175, then the module failure rate of the average annual failure rate of 1.75%. That means the module may (note that it may) fail 1.75 times in a year.