Welcome to Connect, @jarlan. Doctor’s generally look for trends in blood results. That can be coupled with symptoms to determine if there’s cause for concern. One thing to keep in mind is that a test result outside the reference range may or may not indicate a problem. Since many reference values are based on statistical ranges in healthy people, you may be one of the healthy people outside the statistical range, especially if your value is close to the expected reference range.

However, anytime there are consistent counts out of the ‘norm’ it usually warrants some followup to make sure there’s nothing underlying. Blood conditons can take many years to develop and as you’ve seen, for 10 years there hasn’t been anything significant.
But to answer your question, yes, having low blood cell counts can have side effects. Basically, our blood consists of 3 categories of cells…red and white blood cells and platelets. Each type plays a specific roll, so a depletion of any of them can throw off a normal balance.
Too few platelets, referred to as thrombocytopenia, can create issues with prolonged bleeding, bruising, frequent nosebleeds, headaches, etc., Too few red blood cells can create body aches, chest pain, weakness, fast heartbeat, and shortness of breath.

Posting some links below to give you a better understanding low platelets and low red blood cells:
https://www.mayoclinic.org/diseases-conditions/thrombocytopenia/symptoms-causes/syc-20378293
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https://www.verywellhealth.com/living-with-low-platelets-what-you-need-to-know-2252431
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https://www.verywellhealth.com/what-is-pancytopenia-2249143
Seeing that this has been your normal for 10 years, have you experienced any symptoms or changes in health over that time? How did you discover the gap in information from the past decade?