Impact of iron deficient anemia

Some fantastic information in here, thanks everyone.

I have borderline low iron levels and has an iron infusion around 2 years ago as the supplemental iron tablets did not increase the levels. I already eat a very varied plant-based diet and really focus on incorporating all of the nutritional tips and tricks to maximise iron absorption (but there is always more to learn).

My question is how long the iron infusion “lasts”? Recently I am experiencing fatigue levels that don’t really correlate with the amount of training that I am doing and wonder if i need a "top up? Has anyone had any experience with infusions?