Performing a bedikah on an onat perishah is a halachic requirement, and cannot just be waived. However, in this case, you may perform only the bare minimum: that is to say, one bedikah for each onah, and one onah for each veset (not also the onah beforehand, which is a common stringency). Thus, you should do one bedikah each on the onah beinonit, yom hachodesh, and haflagah. Since the first two overlap about half the time, this will mean two to three bedikot total for the onot of any given cycle.

Something else to note is that onot are generally observed only based on a flow, not staining. So if you previously became niddah only through spotting or through a stained bedikah cloth, you would not observe onot based on your last cycle. Please get back to us with details if you'd like to further clarify this point. It also might be helpful to review our articles "Stains" and "Toilet Paper".