From what I've seen of internet reviews on purchase websites in general, I think quite a lot of them can be divided into two camps? Those from people who have only just received what they've bought and are initially pleased with their purchase (or the size/design/colour wasn't what they thought, etc.), and those who've bought and used the product for a while and have written about their experience.
Of the two, I personally tend to be more interested in the latter; it may be useful to read general reviews about sizing, speed of delivery, how well or not something is wrapped or boxed, and whether or not the courier left the parcel at the wrong house, etc., but that sort of review doesn't tell me much about the function, durability and longevity of the product.
Whilst I tend to look for a general consensus of opinion in reviews, what I place most weight on is how many reviews say something along the lines of 'Great product, I bought this 18 months ago and it's worked/worn/lasted so well that I've returned to buy another one while it's in stock/on offer/still available", etc.? The other thing I look for is whether or not the item is the same as the original that's had all the 'old' reviews. If it has changed, is the new design, shape or quality the same as the original, or might it be better or worse? Well, that's my take on reviews, the opinion of others may differ.