I have read somewhere that it is better to randomize the order of your data several times, and perform each time the corresponding ulterior kmeans analysis, to be sure that your clustering results are consistent (reproducible). In this way, you would be able to find and define clusters that have not arisen by chance.

If that is the case, my questions are:

• Should you randomize the order of rows (samples) or columns (variables)? Or both?
• How many repetitions (that is, repetitions of randomization plus its corresponding kmeans analysis) would be convenient?