How did you know when to upgrade?

Quite literally, I grew out of my first camera :)

A bit of real-life honesty? I was rather stubborn about starting with a film camera, regardless of my dad's suggestion to consider digital. My best friend at the time started with film, annnnnd I merely followed her example. He watched out for me anyway, and made sure the lenses for the film camera were digital-friendly so I could keep using them when I (again followed my friend’s footsteps) and moved to digital a year or so later. (To her credit, my friend had no idea, and to my dad’s credit, I’ve learned to take his advice seriously!)

How did you decide on what cameras to buy?
My first digital camera was a Canon Rebel XT (the afore-mentioned film camera was a Canon Rebel, so it made sense to stay with that line) a step up from the family digital camera that I started our blog with away back in 2005 (away back as in megabyte memory cards vs today's gigabyte storage!). I shot my first wedding on the Rebel in 2008, and used it faithfully up until 2013. By then I noticed some odd lines in my photos that degraded the quality and were hard to edit around, and I started to look around for an upgrade. Second-shooting gigs and portrait sessions started filling up my calendar, so to give my best work required a newer tool. A used Canon 5D Mark 1 joined my gear family in February of 2013. It has performed beautifully, and is still going strong. Last December I added a used Canon 5D Mark 2 to my clan which is much better in low-light situations (such as receptions) than the Mark 1, and I’m looking forward to putting it through lots of projects this year :)

Are you going to upgrade again?
At this point, I don't know. A 35mm lens will probably come first, as I don't have a working wide angle lens, and then perhaps a rolling gear case to store everything in. So far the bodies I have are just great!

So, how do I know when to upgrade??
Some things to consider are:

Expertise: how long have you had your current camera? Your eye & creative mind is where the art comes from. The camera is merely the tool to make it reality. Thus, as fun as it is, all the bells and whistles, promises of stellar images, and the rest of the sales pitch that goes with sparkly new gear won't make you a better artist. Only you can make it happen, and you may be surprised at what you can create if all you have is the mere basics & available light! If it is a relatively new model (even if you bought it used), it should last a long time depending on...
Workload: how much do you shoot? What do you shoot? Weddings & events require the ability to shoot in low light, and commercial work requires high resolution images. Portraits, food, travel, home life, etc. can be made beautifully with lower end (even crop-sensor!) camera bodies which leads us to...
Budget: can you afford it? Maybe instead of a new camera, you might invest in a better lens? Or another need for your work or business? Gear is fun to buy, bills are less fun to be responsible for yet are needed to keep things running smoothly. Gear will not make you a better photographer, but getting out there and using what you have will :)

Hopefully, some of your questions were answered, but if you have more, drop me a line and I'll do my best to help!

To close out this techy-type of post is a thoughtful article by my friend Patience. Leave her a comment and tell her I sent you! :)
http://thebrightnessproject.com/i-want-to-take-my-work-to-the-next-level-what-camera-should-i-buy/