In the past, photography is not as easily available as it is today. Analog cameras had films that need to be processed first before you can even see the pictures. And further back, they used to have cameras that produces a mini explosion when shot.
Now a days, anyone with a camera equipped mobile phone can take pictures and videos with ease. If you want better quality and more options, you can use small digital cameras like fuji digital cameras. And for more depth and detail you can go for the expensive high resolution DSLR cameras.
So make sure that your camera is always ready for important events and happenings and document your life properly. This way you not only get to have a nice journal for future use, but you can also be aware of things that are happening and things that you need to change or improve.