Silly question about hair and highlights..

[asblackasyoursoul]

Natural hair colour is dark brown and I have a full head of caramel highlights in but they've grown out about 2 inches now, however they blend in well with my natural hair at the moment so not a concern

However I think after they grow out I may just want to keep my natural hair for a while, give it a rest from highlighting. But I've just thought.. how do I fix it when half my head is dark brown and half is caramel coloured?!
Sorry this is probably a really stupid question but I've had highlights consectively for 3 years now so this would be first time not getting them redone!

[Thistles24]

I’ve done it 2 ways- just had a brown dye put through my hair (which fades quite quickly so is high maintenance) or having “stretch roots” highlights, so you have them done at different heights, if you see what I mean? The result is you don’t have a line of roots, they’re all at different levels so looks more natural as it grows out.

[JanewaysBun]

I have previously used box dye to blend them and then transitioned to my normal colour if that makes sense?