It's certainly "case by case, every time", but in every case the first thing should be customer education. If your customer wants a feature done in an unreasona

It's certainly "case by case, every time", but in every case the first thing should be customer education. If your customer wants a feature done in an unreasonable timeframe, don't say yes, don't say no, educate your client how long it takes to properly implement the feature. Not educating clients is the worst thing we can do as software professionals. Why do most people not ask for a house with a rushed foundation or frame? Because most people know that that's asking for serious issues later. Why do most clients ask for key software for their business rushed out the door and delivered ASAP, sans testing and without proper spec? Because most don't know that they're asking for serious issues later.