A person with normal insulin sensitivity and production, eating normally, should rarely spike and only very briefly. A healthy body has insulin ready-to-go to deal with food as it arrives and then has a second wave of insulin under production to mop up any leftovers.
The point after eating, when your sugar levels are highest, will depend on you, what you have eaten, what you are doing etc. If you are getting a serious spike at 15 minutes or half an hour, you might want to question what you are eating. It would suggest that your first phase insulin response isn't good.
Over the years, quite a number of people on here have said things on the line of "my wife, who isn't diabetic, spikes to 10 after chocolate cake, so that's normal, so I'm not bothered if I do the same". I would suggest that The Mrs is also on a road to diabetes, even though not officially diagnosed.
At first, it is very interesting to run a series of tests, say every 15 minutes, after a food such as porridge, to see what happens. After that, sticking to one hour (or two) enables comparisons. In the end, it's all about avoiding carbs. Do that and your levels should be low.
Sally