Electrical work is one category where the cost of a mistake is much higher than the cost of hiring a pro. Some basic work is generally homeowner-doable. Anything inside the panel, anything involving the meter, anything older than the homeowner: that's licensed-electrician territory.
Outlets and light fixtures — mostly fine. Anything in the panel — no.
100-amp to 200-amp upgrades are pitched constantly. Here's when you actually need one.