Strength training is a "MUST DO". It shouldn't be optional or an afterthought when it comes to your home fitness program. The benefits are too great to ignore...
Shoulders help maintain proper posture and help with lifting
Arms lift things and help move your body
Back helps support and move your body and helps prevent injury
Chest helps maintain posture and helps with lifting
Abs help with everything!
Legs help balance and move your body
You can use any or all of the following types of exercises to build strength. This is not a complete list but these are the most common options. Use whatever works for you in any combination based on what equipment you have available or whatever mood you're in.
Key Points for all of your training sessions
If you're just starting out, choose 1-2 exercises for each muscle group. That would be 6-12 exercises for a complete full-body workout that you could do 3 times a week. There is an almost infinite number of exercises to choose from and many ways to create a routine.
Of course, if you're more advanced, looking for variety or if you have more specific goals, you can choose more exercises for certain muscle groups or split your program so you're concentrating on specific areas.
Regardless of how you choose to schedule your training, leave 48 hours between sessions that work the same muscles.
You actually get stronger BETWEEN workouts, not during. So rest! Your muscles need it!
Choosing a rep range
Once you've picked your exercises you need to pick an amount of weight or resistance. Pick a weight that you can lift 8-12 times and only 8-12 times! Be honest and push yourself. If you get to 12 reps don't just stop because you counted to 12. If you can do more reps then the weight is too light and next time you need to increase the resistance. Challenge yourself and keep challenging yourself. Don't just go through the motions.
Choosing a set range
2-3 sets is a good starting point and the recovery time between sets can be as short as 30 seconds or up to 3-5 minutes depending on how heavy you are lifting and your goals. The number of sets can also vary within a single workout if there is a specific muscle group you want to target more.