Perficient

I think clear coding is much more important than efficient coding. 

Long ago, the development arena was much more inclined towards making the code more efficient. The focus remained majorly on how much functionality can be packed into a single kilobyte of storage, how much RAM it uses, how tightly it complies, what extent of communication would be sent in every network packet, and so on. Those days, computers even fail to have random access to persistent storage and one program at a time could run. RAM was also measured in bytes than gigabytes. However, the time has changed now. 

Proficient programmers never ignore the efficiency of writing good code. But, now they also pay attention to the cleanness of the code. This mostly boils down to readability and comprehensibility that helps you in reusing the code. You will be required to reinvent the wheel many times. It would also be perfectly well if you decide to write the code from scratch than using whatever you have already written. 

Problems are similar whether you are working in an open-source or closed source environment. But when you know your own code, bugs can be easily fixed, and features can be easily added. When the code is clear, you will have a better idea of the sort of using certain functionality. This actually eliminates the need for rewrites. 

As long as your code meets the basic requirements for the efficiency needed to meet your requirements for the immediate future, clarity wins the race to efficiency. Even the coding experts suggest forgetting about the small efficiencies. Stop going to the premature optimization that reduces clarity in coding.