Vanda flowers looking a bit sick
 

Hey,

My vanda has been in flower for about 3 or 4 weeks, and now the petals are looking a bit brown and slightly translucent.
Is it botrytus?

Should I cut them off or just let them die and drop on their own?

3 to 4 weeks that a good stretch for any flower and if it was sick it would not have lasted but a few days :).

You can cut a flower any time you feel like it. Its your flower :)