The thought experiment of changing the violin strings is interesting. The first thing that struck me was the nature of the question and what was being asked.

Its not possible for an individual to change all the strings of a violin at once so the question needs to be clarified. Is it better to change one string as required or replace all the strings when one string needs replacing? And that is a totally different question and brings up questions on how we view change.

Regardless of the answer in both scenarios, with all strings replaced or not, all the strings would need to be adjusted.  I also suspect that there is an optimal order in which the strings are replaced and adjusted so being knowledgeable and having a good ear (aware) are necessary requirements to making the change successfully.  And of course the strings need to be constantly adjusted to stay in tune so change is a process that does not stop.

In the way the question was asked there was an assumption what was understood by stating that all the strings could be changed all at once.  Depending on where one perceives the change you could equate the process of change as multi tasking. However if we were to watch someone change all the strings of a violin we would see them changing one string at a time. This to me begs the question what is change and how do we perceive it.

My experience of change is that change happens slowly then all at once. Meaning we are not usually aware of all the micro changes that have to take place before we notice change.  Many also have the experience of everything changes and staying the same. Once a single or all the strings were replaced on the violin did the violin change?

With regards to multi tasking I personally don’t believe ego consciousness is capable of it thought the unconscious is. (in the unconscious there is no past, present or future, everything happens in the same moment.)

Ego consciousness is linear where each moment appears to be the product of cause and effect and that this creates the experience time and movement or change. Ego Consciousness divides experience into units of time and process them in that way, one at a time. Instead of multi tasking Ego Consciousness more likely does something like time division multiplexing. Meaning we direct our consciousness on a number of tasks one at a time. We may do this so quickly that it appears we are multi tasking however we are not. We are still focusing our attention on one task at a time, we are still changing one string of the violin one at a time.

I think being conscious of the illusion of multi tasking is important to the process of making changes in our lives. If we have a tendency to focus our limited attention on multiple tasks we many not notice that the first string we attach to the violin is flawed in some way. As well we may not notice that below the surface at a subconscious level many things are occurring that might influence what we hope to change. Its possible at a deep level we might really want to pick up a guitar