I think only one other guy here mentioned Squats. They make you strong all over. Do them right and make em count. They should be a core part of your routine. Once a week followed by an adequate rest day or tow depending on how fast you recover. Don't overtrain! We ain't no spring chickens no more!
Down the road, in a gym far away
A young man was heard to say,
"No matter what I do, my legs won't grow!"
He tried leg extensions, leg curls, leg presses too.
Trying to cheat, these sissy workouts he'd do!
From the corner of the gym where the big guys train,
Through a cloud of chalk and the midst of pain,
Where the big iron rides high, and threatin' lives,
Where the noise is made with big forty-fives,
A deep voice bellowed as he wrapped his knees,
A very big man with legs like trees,
Laughing as he snatched another plate from the stack,
Chalked his hands and monstrous back,
Said, "Boy, stop lying and don't say you've forgotten!
Trouble with you is you ain't been SQUATIN'!!"