How far can sensors be from Base Station?

@davey_d​ 
What about lathe & plaster walls?  How many walls can the signals go through?

I see https://www.instructables.com/Boosting-Signal-Range-of-SimpliSafe-DoorWindow-Sen/

@brycen ,

That wouldn't be something we can give a definite answer to, since every home is going to be different. The simplest advice I can give is to try it out in person - put your system in Test Mode through the Keypad, then try the Entry Sensor in different spots. 

And as for modifying sensors for better range - mileage may vary on that too!