What follows are the criteria I use to determine what to script or automate first, second, and so on. It's another of the "it depends" questions that never have an easy answer. I will try to help you make some rational decisions but ultimately it's your world to live and you need to decide.
The thing I see everyone want to do first is automate and that takes the longest to do. That task takes the better part of a week to complete because you are constantly getting pulled in a hundred different directions. This is not the first thing you need to automate or should automate. Not that the duration of the task isn't important but the number of times you have to do it, is more important. I may only spend 2-3 minutes compressing some logs on a development web server. If I am doing it on 10-20 various servers every week it's not only annoying but it's sucking a lot more time because of the context switching it's causing. There is also the cost to your company in the time spent by the users of the system trying to troubleshoot the full disk.
So how do I figure out what's sucking up all my time? Do I track everything I do all the time? Heck no I don't. I use a simple spreadsheet to track my work for 3-4 weeks at a time. I repeat this every 3 months or so. Then look at what I spent my time on. I track smaller items with just tick marks and an average time to complete the task. I don't worry about what time of day it is. If you want to note the time it takes you for longer tasks it will give you better data but not necessarily better results for this purpose. Remember the time you are spending on individual tasks isn't as important as the number of times you have to repeat it.
Now let's flash forward to 3 weeks from now after you have some data collected and answer the following questions.
- What are the top 10 issues you resolve on a regular basis?
- Are any of the tasks on the list affecting mission critical parts of your organization? Do you think you should add them to the list? You will likely want to add them and pay close attention to the next item on these tasks.
- How many steps are there to automate in the top 20 tasks you do to resolve these issues? (Exact numbers are not needed, just a really good guess.)
Your top ten list plus the items affecting Mission critical parts of the organization should be your starting point. To further narrow it down start with the items with the least number of steps. When doing this though make sure none of the steps are "Install the OS" or "Install Oracle". Those task steps are not really one step but multi-step tasks on their own. Now that you have your list ask someone else for input. Be sure to provide them with the complete list. I have often described myself and co-workers as being on a mission when they start automating. This is great, shows focus and determination. It also can in some cases cause mission blindness. You want so badly to automate that really hard thing that you miss the quick wins lying at your feet. Asking someone else to look at your lists will hopefully help you keep from being blind.
Take your own time if you need too complete the list. As much as the company will benefit from your automation efforts, your work life balance will be the most improved. So spending a little of your time up front will give you more of your back time later.
If you can reduce a series of tasks you do daily that takes 30 minutes into a single script that runs in 30 seconds over the course of a month you will have 9 more hours to do new scripts. You will also gain from the lack of typos the script will make on Monday mornings. If you can take that same script and have it run as a scheduled tasks (think cron or at commands), then you can get back the whole 10 hours to put back into scripting the next thing.
Remember the goal of automation is to free you from the mundane tasks so that you can work on the more complex and proactive ones. You will never stop feeling like you are spinning your wheels if you can't get out of the daily repetitive mud. Automation is the way to push yourself back out onto the proactive route you have been looking to reach.