DanBow

@DanBow no, NTAH. Flexing on the poors? Maybe, but if someone thinks that £30 is too expensive to be sacrificial then I'd say airsoft is not the hobby for them.

@Skara thermal? Depending on nm range there is fairly inexpensive (relatively speaking) Germanium lens protectors on AliExpress.

Well you pay your money and take your chances, get lucky and your sight will have a full and rewarding existence. 

If not you get a new sight and start again.

Stay lucky @DanBow.....

I tend to use some form of protector on both my torches and optics - it's all rather cheap/easy to do, and doesn't affect the optics quality (at least in terms of typical airsoft use - and with the notable exception of the protector that I put on a replica eotech that warped the image so much it made it unusable). I buy a number of perspex ready cut discs in various sizes off ebay, and fit them to the front of scopes held in place by a flip up scope protector cap or a self adhesive ring of foam purchased from aliexpress, and on front of torches using a 3d printed collar. £1-2 per protector vs £30 or more scope...