Is replacing a turbo a big job?

Could you elaborate on the complexity of replacing a turbocharger? Is it a minor undertaking or a major overhaul? Would it require extensive disassembly of the engine? What kind of skills and expertise are typically needed to perform this task? Are there any specific tools or equipment required? Are there any safety concerns that need to be addressed? Furthermore, could you provide an estimate of the time it would typically take to complete the replacement, and if it's a job that could be done by an amateur or if it's best left to a professional mechanic?