There have been several benefits offered by extended use and reuse of respirators. The most common benefit would be conserving the limited supplies of disposable N95 Mask Singapore. There would be several concerns raised about these practices. A majority of devices may not have been cleared by the FDA for reuse.
There have been several products from manufacturers coming with user instructions recommending discarding the product after every use. There have been several others enabling the reuse if permitted by infection control policy of the facility. The most significant risk would be that of contact transmission from touching the surface of the contaminated respirator.