What if all the developers are busy, but the ambulance is constantly "wedged" because of which the deadlines for projects suffer?

Question

Project management

A banal situation - there are several developers, each with a project and each with their own deadlines. In the process of their implementation, an ambulance arises for 15 minutes - 5 hours, which must be performed "here and now." Because of this, the timing of final products suffers, sometimes severely. How to be? Constantly notify customers? - You wind up. Increase development time taking into account risks? ... a strange undertaking if the risks are not related to the customer's project. They are not rubber. This is where this question comes in.
Maybe it's a classic. I welcome any comments and references.

Answer 1

Allocate a certain amount of time for such fixes. Days a week.
Sometimes a couple of days a week will come out, sometimes no time will be spent. Such fixes are a normal workflow.
As for customers, also add +20% to the development time.

a strange undertaking if the risks are not related to the customer's project.

You don't work for him, but for your company.

Answer 2

Designate people who will deal with the emergency room on a regular basis. Thus, the working group dealing with scheduled tasks will not be distracted by unforeseen tasks. Emergency tasks are performed as part of product support.

Answer 3

Any ambulance is sold just three times more expensive, this is enough to take another two or three programmers from above.

Answer 4

Urgency arises regarding what? Here I have a product "A" and I'm doing it. Herax, ambulance, where does it apply? For project "A"? To the project "B" that Petya, who is sitting on the left, is busy with? To the project "Zh" which has long been commissioned?

Answer 5

It is necessary to hand over the project completely ready and discuss all the corrections after the delivery of the work, if the customer is ready to pay for such corrections, then why not do it.
+ Corrected the project, the customer does not need to look for freelancers or a studio.
+ Earn a penny.
- Lost time.
This is a common practice in web studios, when you fix old work during a new project, try to reserve time in a new project, you won’t get away from this, because there will be more disadvantages if you refuse the customer.