This is aimed at IT geeks primarily, so the rest of you can do what you typically do when viewing my blog: sleep.
Think about each question carefully... As it pertains to growing a small environment into a larger environment...
1. At what point do you switch from workgroups to domains?
2. At what point do you setup centralized patch management?
3. At what point do you implement a means for remotely installing software on all computers?
4. At what point do you begin automating inventory reporting?
5. At what point do you switch from internal mail hosting to external? Or external to internal?
The answer is?... When it's convenient. Yeah, I could dive into all sorts of painful metrics and ROI-ish rationale, but really, it comes down do convenience. Even when the raw numbers prove to be a wash, the tipping point is gut feeling. That dreaded morose feeling when you think of one more day of doing things the same way you've done for way too long. The appeal of taking one more thing off your daily plate and freeing up time, hassle and also streamlining your environment, usually tips the ball into the new court.
The point is that with all the technology, all the fiscal analysis, all the economic pressures, the biggest deciding factor in major technological transitions is human emotion and human perseverance.
Some additional thoughts
One of the most common, and most commonly overlooked, concerns of many IT professionals is figuring out where their environmental "scale" sits in comparison with other environments. Most of us think we have a large environment. Or we think we're in a small or medium environment. Whatever. But how do you based that assessment? Most of the time it's based on subjective reasoning based on conjecture and anecdotal information.
I have no idea what that last sentence meant, but it almost sounded like I did. But really what I'm trying to say is that we base our self-awareness on what we learn from talking to peers, reading articles, blogs, and so on. We hear from six people that 30,000 computers is a large environment so we assume our 10,000 computer network is "medium". But to someone with 250 computers, your 10,000 computer network is indeed "large", while to a 500,000 computer network admin it's a small environment. It's all subjective.
I remember having a conversation with a Microsoft engineer years ago while rolling out SMS 2003 just before it was RTM. After months of working in the beta program I was ready to roll it out but I had a question about architecture with respect to the size and geography of our environment. I asked if 5,000 computers was "medium" or "small". He said "well, that depends." I said "on what?" He said "how are they located?" They were indeed dispersed widely across the U.S. That led to another hour of chatting, but the take away I remembered was that even that isn't a hard-written rule. It too was under the subjective view of a human.
So, if you're feeling confused or even a little in doubt regarding how to size up your environment, don't feel bad. Even when it directly impacts decisions about how to plan and deploy a new product, don't be fooled by vendors making confident statements without doing your own analysis and comparisons.