HELP! Exercise question..

I'm split between two different ways of approaching pull ups/pushups. The first obvious way is to do a quick pushup or pull up workout to failure every other day. The second way i've heard is to do them throughout the day and never go to failure while increasing the volume everyday. I'm not looking to gain mass so my goal is just to build strength but i'd like to hear peoples input. Right now I usually do pull ups a few times a day for 3 reps each time. I'll do them really slow and controlled so each set takes about 15-25 seconds.