I have 17hr fly time on my props - should I replace?
No visable damage.

I am asking because they are relativly cheap and if there is a risk of wear and tear I dont mind throw them away

In another thread DJI said replace them every 3 months.  https://forum.dji.com/thread-186968-1-1.html

DAFlys Posted at 2-10 02:38
In another thread DJI said replace them every 3 months.  https://forum.dji.com/thread-186968-1-1.html

thanks .... I think 3 months is a bit far fetched. did they give any particular reason?

mouthpiec Posted at 2-10 02:44
thanks .... I think 3 months is a bit far fetched. did they give any particular reason?

No,  Personally I replace mine when they are damaged not not before.  

Hello and good day mouthpiec. Thanks for reaching out and for the inquiry. If the propeller of the said drone is scratched, bent, or damaged please replace it immediately to avoid any untoward incident. It is also recommended to replace them at least every three months for proper maintenance of the said DJI drone. Thanks for your valued support and have a safe flight always.

DJI Stephen Posted at 2-10 10:38
Hello and good day mouthpiec. Thanks for reaching out and for the inquiry. If the propeller of the said drone is scratched, bent, or damaged please replace it immediately to avoid any untoward incident. It is also recommended to replace them at least every three months for proper maintenance of the said DJI drone. Thanks for your valued support and have a safe flight always.

thanks for your reply .... is there a particular reason why props need to be replaced every 3 months?
my props have 17hrs of fly time, never touched anything, no scratches etc.

I dont mind replacing them, but I would like to understand the reason behind it.