I have been working out for about 3 years and am still attempting to make the optimal routine to maximize growth in my arms. It is a tough procedure and honestly varies from person to person since nearly everyone's arm workout varies.
What I have found best for myself is working out bis and tris every 3 days. Bis, tris, off, bis, tris, off. And with my 5 day splits on back, chest, legs, shoulders, etc. you wont have a stagnant routine.
When working arms, I never go for a certain amount of reps. I do try to keep them between 12 and 20 but what youre looking for is a solid pump. And your bicep routine shouldnt exceed 35 minutes. If it does, youre taking too long between sets or exercises. Try out super sets and drop sets. They work wonders for the arms.
Another thing is make sure you arent going too heavy to the point where you are sacrificing form. I always try to keep my arms parallel to my body (and sometimes pulled a little bit behind my side) and my hands shoulder length apart. But the key I have found out is really limit the time between sets to 30-45 seconds and do alot of drop sets and super sets.
Try it out and let me know if you like it!