Bond energy explanations say the number given is often an average.
For instance, in methane, the $\ce{C-H}$ bond dissociation energy is the total energy required to remove all four hydrogens, divided by four. $(\pu{415.5 kJ/mol})$
But, removing the first hydrogen atom is harder than the second or third ($\pu{439 kJ/mol}$ for the first). Why?