Are Self Publishing Services Worth the Investment?

Has anyone tried self publishing services and actually seen real results with their books? With so many companies offering editing, design, distribution, and marketing support, it’s hard to know which services are genuinely valuable. Do these services make a bigger difference for first-time authors, or are they equally useful for experienced writers? I’m curious to hear about personal experiences what worked, what didn’t, and whether investing in professional self publishing services truly helped boost visibility and sales.