Flying non stop is the fastest way to get to your destination but for many people that is not an option. Many airlines have adopted the hub and spoke system and don’t offer non stop flights except between major cities. Also some of the cheaper flights are going to have you making a connection.
When making your reservations how much time do you need to connect? Many airlines set a minimum connection time (often 35 minutes) but the true answer depends on a number of factors.
Have you been to the connecting airport before? Many airport have very confusing maze like layouts. You can usually find maps online but sometimes you won’t know your connection gate until after you depart. At a large airport it can take 15 minutes to get from gate to gate. Add to this the fact that if you are at the back of the plane it can take 15 minutes just to get off the plane and that is 30 minutes right there.
Are you traveling alone or with others? The larger the group the more time you will need to connect. It can take time to get everyone organized. Some people might need to stop for food or use a restroom. Not everyone walks at the same pace.
Have a stroller or need to wait for elevators? This is going to add some time, but also traveling with kids will add time anyway. Children need a chance to play and explore and enjoy their travel experience. It is best not to rush them.
What time of year are you traveling? Summertime thunderstorms, especially in the afternoon, are going to cause delays. Give lots of extra time for this.
The short answer is some connections can be made in as little as 35 minutes but longer is better. I would recommend at least an hour and a half and even more if you have small kids.