Think about coding as using CSS sprites. They are far quicker to load, because it cuts out all the back->forward->back->forward between the server. This is the same as alt+tab alt+tab all the time. Even though it may only take 5 seconds or w/e (or checking your coding in multiple browsers, that could take 30 seconds) it adds up, given that you'd check it 10-20 times per job. That means you could save 5 minutes per job (checking 10 times instead of 20), just for coding more before you check in the browsers. Even if you just did 1 job a day, thats 30 hours a year you have saved yourself checking in browsers when you didn't really have to. Save 5 minutes a job by writing all the HTML first, then the CSS, you've said yourself another 30 hours a year. You could save 60 hours a year just by changing your process slightly! I worded my example badly but it proves my point. And it applies to anything - act as if you've got a gun to your head which will go off if you don't get the job done in an hour. You'll find you can get it done sooo much quicker

Morale of the story? Keep finding ways to cut out 5 minutes - browser checking, HTML then CSS, emailing client, writing posts on forums...