I dunno ... I don't bother telling my manager what I'm doing. He asks, "is it done yet?" and my usual answer is "yes." That suffices. The fact that I spent 2 hours writing a tool that did my job for me instead of 3 hours doing my job isn't something he concerns himself with.

Sometimes, I admit, it's reversed, but only for tasks I know I'm going to do a second time. So I'll spend 4 hours writing a tool to do a job that it would take me 1 or 2 hours to do by hand. But it's a tool I'll use 5-10 times over the next year, so by the next deliverable, I've saved the company maybe a full day's worth of my time which I can spend on other things.

I have an entire development environment (originally written for 4OS2, now ported to ksh/bash, since my job description has changed from OS/2 to Unix/Linux) which I've spent literally weeks of time on, but which has saved me literally months of wasted time, not to mention my teammates who also use my environment saving countless person-months over the last 5 years.

My manager simultaneously warns me not to spend too much time on it and lauds me for it in front of his manager - it has made my yearly review a few times already.

Of course, this is the same manager who told me explicitly not to create a team website, and then, when I did it anyway, put it in my yearly review as another positive (I actually save time that way, too, since it serves as a repository of FAQs to which I can point people so I don't need to retype answers all the time). Or, when handling our testplan, explicitly told me not to put it on the web, and explicitly not to use an RDBMS to store the testplan. If you're following the theme here, you can guess what happened: it made my yearly review 2 years in a row as more positives. I spent literally weeks designing, coding, and writing for these sites. And our team literally saved months of effort and management got instant, up-to-the-second status reports any time they wanted. Which saved me hours of work right there - those status reports could be requested in the middle of a meeting, and were painful to produce. ;-)

Moral of the story: like anything else, you gotta know how to sell to your audience. Sell yourself and what you did for the company. Short term always matters more than the long term, unless you have an especially gifted management, which is very unlikely in a publicly traded company.