Question: I think more frequent salary raises would be good for employee engagement. Rather than an employee "holding their breath"/working for a year and asking for a $5000 raise, why can't the employee feel comfortable asking for a $416 raise every month?

I know there are strong cultural norms surrounding this, but i partly suspect that all of the norms originally evolved in reaction to administrative and technological realities of processing employee pay raises in resource-strapped HR departments. Are there known barriers: HR technology, Legal, Accounting, Executive mindsets (business training?) that interfere with more frequent, low quantity salary increases?

Answer: 
> 
> Are there known barriers: HR technology, Legal, Accounting, Executive
>  mindsets (business training?) that interfere with more frequent, low
>  quantity salary increases?
> 
> 
> 

Companies budget annually. They occasionally revise them quarterly, but seldom monthly. This makes is harder to give unplanned raises each month.

It takes a lot of work to go through the evaluation process that leads to raises. A lot of discussions, a lot of approvals, a lot of paperwork. No manager I've ever worked with (and certainly not me) wants to go through all of that more than once per hear. Most hate it annually.

Next time your annual raise comes up, you should propose that you don't get your full raise all at once, but instead get the same amount parceled out over a 12-month period. Be a pioneer and see how it works out. I can't see how this could be a good thing for you, but perhaps your company will.
If all you're rewarding employees is once a month or worse, once a year, there are bigger problems. 

Most managers should spend just about every moment at work supervising, evaluating, motivating, and rewarding their people, but they're given many more responsibilities or they prefer other tasks and barely have time to do an annual evaluation let alone monthly. There are some that suggest tying employee compensation to things that can be measured more objectively: sales, customer satisfaction, return rates, support calls, on-time delivery, etc. After all, if your actions aren't making the company money, how can they pay you more?

Your suggestion could be addressed with more frequent bonuses just like other commissioned employees. The more a reward is delayed from the behavior the less effective it can be. Even if HR couldn't keep up with monthly payments, at least you would know you earned the reward.

If the practice were more common, the payroll software apps could be built to handle it with less HR staffing efforts.

It's just too easy to keep up our lame annual reviews and subjective bonus systems that probably demotivate employees as much as anything else. According to [Aubrey Daniels in the book Oops!](http://aubreydaniels.com/oops-1-employee-month-eom) you could double the efficiency of annual reviews if you did them every two years. Yes, they're that worthless.