Flexible circuit board circuit

There are many restrictions on circuit wiring, especially the parts that need to be twisted back and forth. Improper design will greatly reduce its service life. 
In principle, the FPC with single-sided mechanism is required for the parts that need to be used in a zigzag way. If it is necessary to use double-sided FPC due to the complexity of the circuit, the following points should be noted:
1. The zigzag part is additionally made with single-panel FPC, and then it is connected with double-sided FPC.   
2. If the through-hole is not used, the through-hole in the zigzag part need not be plated with copper.   
3. See if you can use a through hole (not one). Because the plating of through-holes will have a negative impact on the bending resistance.