But just when we thought we'd had our fill of them, another one cropped up on our radar – and it might just be the most wearable yet.
What does the clever technique entail? The clue, as ever, is in the name. Where highlights involve lightening the hair, often with bleach, and lowlights involve darkening your strands with colours that are a few shades deeper than your natural hair colour, midlights add a subtle and sun-kissed warmth, typically to the mid-lengths, connecting light and dark tones for an overall much more seamless finish.
If you've ever had harsh highlights or blocky lowlights, you'll know how jarring they can look up against your natural hair colour, but according to Matt Rez, Beverly Hills hair colourist and pioneer of the trend, which is now sweeping social media, midlighting is great because it creates a "blended yet high contrast" finish. Talking about the technique on Instagram, he wrote that it involves "blending the darkest base to the lighter and lightest strands, keeping tonal balance [from] root to ends, and not being too #ombré or #stripy."
The best part? Midlights aren't just for blondes. A quick search of the #midlights hashtag proves that both brunettes and redheads can get in on the action, too, but the key to getting it right is choosing a colour that's quite similar to your natural hair colour in order to bring everything together flawlessly.
Just like highlights and lowlights, some colourists employ foils while dyeing, but to keep the finish looking subtle and lived-in, many tend to midlight hair using the freehand technique – applying dye to strands using palms and fingertips – which is a little less 'perfect'.
We know what we'll be asking for at our next salon appointment...