It all totally depends on the task. My previous job was at a web agency. You give me a spec for your website and I could fairly well nail down how long it was g

It all totally depends on the task. My previous job was at a web agency. You give me a spec for your website and I could fairly well nail down how long it was going to take if I was doing the work. I've found that it's important to give a quote (to your managers) that you almost feel uncomfortable with. Not so long ago I had to quote on integrating a 3rd party ad system into a site. A 30 minute job. I'd already spoken to the 3rd party and didn't trust their abilities to supply working js. I quoted a week (even though it seemed completely unreasonable to me). We used it all. Over time we developed a policy that if we were integrating with an external system we would only do it on a time and materials basis. We might give a guess at how long it might take - but always caveated with a "this is probably wrong" (and we'd totally overestimate to avoid the surprises). I'm now building new technology with a friend (who's not a developer). I don't really make predictions about how long anything is going to take. At first he found it a bit frustrating that there's so much uncertainty - but after witnessing again and again how long it can take to solve a single issue he's come to accept that's just how it is. Two very different worlds.