Question

What are the pros and cons after the WW1 (World War 1)

Answer 1

 the pros of trench warfare included easy access to supplies and food, spare ammunition and guns and quarters were the soldiers could rest. 
The cons of trench warfare in WW1 were that very few people liked fighting in trenches because it took a few months, even a few years to gain a few feet of ground and it caused thousands of deaths for the soldiers.