Shops can range from functional spaces adorned with unpainted wallboard to beautifully finished, painted, and trimmed-out spaces. Ultimately, I think it depends on your budget and how important your surroundings are to your mindset as you’re working, or to your clients’ if they will be viewing your shop. If finishing your shop will improve the quality of the work that you will produce, thereby relaxing or inspiring you, or showcase for your clients the quality of the work of which you are capable, it may be a worthwhile investment. A more finished space may also allow for activities like parties or even a weekly poker game (as long as drinks stay off the tools).
Temperature and Moisture Control. If your workshop is to be located in a portion of your house that is already comfortably warm, this will not be an issue. But if you’re converting a barn or shed or an unheated space, especially if you live in a climate where winter temperatures make for cold hands, you’ll need to devise a heating strategy. In some climates, air conditioning is a virtual necessity in hot weather.
Let’s be clear about one thing: No workshop is perfect for everyone. If there were, I could simply give you a precise plan to follow with clear dimensions. Every person who comes to the hobby, avocation, or profession of woodworking has his own particular collection of tools and his own peculiar work style, skills, and desires for the kind of woodworking he wants to do that gives him a unique approach as to how he will lay out a shop: where the tools should go, where lumber and supplies are stored, and how much bench area he needs.