By Tim Kadlec CHAPTER 4arriving at a budget
Knowing that performance affects just about every important business
metric, the ideal scenario is to make your site as fast as possible. The most
well-known response time targets have been around since 1968, and were
popularized by Jakob Neilsen in 1993^10 :
- 0.1 seconds: The limit for users to feel that the system reacts instan-
taneously. - 1.0 second: The limit for uninterrupted flow of thought. The users
notice the delay, but they still feel direct interaction. - 10 seconds: The limit for keeping user attention. Anything longer
than this and the users will either give up or go off to do something
else while they wait.
Ideally, your site breaks that one second time barrier. Sometimes,
though, that’s not realistic — whether because of the type of site you’re
building, the budget or other external constraints. Armed with knowledge
of the importance of performance, there are two additional criteria to con-
sider when arriving at your ideal budget:
- Current performance of your site
First, audit your existing site to see how it currently performs under
different network conditions. Record load times for these benchmarks,
as well as the number of HTTP requests and overall page weight. - Current performance of your competitors sites
Next, take a look at how other sites in your industry perform. For par-
ticularly important competitors, do the same sort of analysis that you
did for your own site. You can also get a good overview of how sites