If you can get into big trouble you might decide to walk away from a particular challenge. And, that's ok. Our goal is to save money. Not destroy items that a professional could repair. You should also consider safety issues before attempting any repairs.
Electricity is a particular concern.
Make sure that the item is unplugged or the circuit breaker turned off before you begin any repair. Remember that some repairs just aren't safe without proper tools or knowledge and should not be attempted. Heights and heavy objects can also be dangerous. Remember that your safety comes first. Before you attempt any repair spend a little time thinking about how the item works and what the symptoms are.