I think that many people think of STHF as TEOTWAWKI. I define them as this.
TEOTWAWKI:
Long term disruption of society. Collapse of government, civil war, massive war on our soil against an aggressor, nuclear war aftermath, etc. This is a breakdown of society in which there is no end in the foreseeable future. This is more of a Mad Max type of situation, an Enemy at the Gates type of situation or a 28 Days Later type of situation. I am using movies as descriptions as it is easier than verbal description. In this case, order is not coming back or not as we know it now, or not for a long time, months or years. These situations are not likely to happen and most can not be properly prepared for by most people due to the financial cost to prepare for such. This would run into the half million plus cost to be totally prepared for total self sufficiency for years at a time. The only people that can come close to being prepared for this is farmers. Even then not all of them would be able to self sustain for years.
SHTF:
This is a scenario in which there is a short term loss of order in society. Power loss, water loss, riot, tornado, snow storm, train overturns with toxic substance, etc. These cases will not last indefinitely, order is foreseeable, and expected. There will be accountability for any actions taken in these circumstances. This type of scenario would last from a few days to a month or two maximum. These are the scenarios that most people can prepare for.
The differences in what you would do in these is quite different. It may also vary depending on the situation. Such as a tornado wiping out your house and everything is gone. You are not going to sit down on the foundation of your house and stay there for the next 6-12 months as a new house is built there. You are going to find a new place to stay. I think that most discussions need a defined circumstance to better outline the situation to get better answers as to what people would do and what equipment they would use. I think the problem is that many people are thinking of a situation such as TEOTWAWKI when SHTF is listed as the situation.
These are my definitions, others may disagree with them. As long as there are definitions for both types of scenarios, I don’t care what you call them.