Do you ever feel like things are down to the wire? Like you are up against time once again? My suggestion is to always allow two weeks.
There are a lot of things going on in life. And unexpected delays can occur. Actually, its not necessarily unexpected delays in my experience. It is more often delays, or actual timeframes, that could be expected.
For example, sending Christmas gifts overseas in late December and expecting them to get there on time is unnecessary stress. It is just very unlikely it will happen.
Last year, to send to Canada, using international standard mail, you needed to post before the 14th December from the UK. But you have to buy the gift and wrap and send it. And then wait in a queue at the post office. So allow two weeks for all of that before the deadline.
If you are getting a mortgage, always add two weeks to whatever the timeline is. Some people give you an accurate, or even a conservative, estimate of the time it will take. However, many will aim for the fastest time it has ever happened. That can lead to disappointment and unnecessary stress.
You always need to add a contingency. Always allow two weeks.