Depends on the soil type. Clay will stick to a shovel like glue and you'll be there all day. A mini excavator with a thumb attachment can grab and place rocks in one motion. Sometimes the right tool is about saving your back, not just moving dirt.
My grandpa built a stone wall by hand in Vermont that's still standing after 60 years. He used a shovel, a pry bar, and a strong back. Renting a mini ex for a weekend project adds hundreds of dollars and you still need a trailer and truck. Most of us just need to dig a few holes, not run a construction site. The old ways work fine if you're not in a hurry.