Each observation should take a fraction of a second. It is called peeking to distinguish it from looking or watching. There is a method to doing this. Think about what you are looking for before you open the kiln. Pop open the kiln to record with your eyes, close the kiln. Think about what you saw. If necessary, repeat. But only after you have thought about what you saw.
Do not spend time looking into the kiln.
Think about the necessity for observation before buying your first or next kiln.
The best kilns are those with generous observation ports, both in number and size. These allow you to peek into the kiln without disturbing the heat distribution within the kiln. Two or more ports are best, as you can shine a light into one of them to illuminate the interior of the kiln at lower slumping temperatures.
If you do not have ports you will need to open the kiln. This is easiest to do with top hat kind of kiln. The top hat kiln keeps a lot of heat in the upper portion of the lid, making the amount of heat dumped less than on other kinds of opening. You can peek in at the level of the shelf, so minimising the amount of heat being dumped.
The problems with lids opening so you have to peer down into the body of the kiln, and with doors opening to the front, is that you are dumping a lot of heat directly at yourself. You also are losing a significant amount of heat from the kiln. The large air exchange also will disturb any dust in the kiln and that may fall onto your work.
It is possible to make ports in your kiln by drilling a large diameter hole in the side of the kiln and through the insulating material (assuming you do not have side elements). This post gives some ideas.
In all the cases where it is necessary to open a lid or door, you must close the kiln slowly and gently to minimise disturbance of the air within the kiln.
The effects on the glass of peeking at various temperature ranges varies between the rise and the fall in temperature. This post
gives some ideas of the effects.