I've only been over my limit when returning not going out.........so makes no odds to me and I would hate to have to shop for essential items once I'm there

I'm also "heavier" coming home, despite using up all the toiletries and suncreams and leaving behind the leftovers never quite figured out how that happens... I dry my beach towels before I come home (wet towels are heavy; I "stash" some of the hotel's bath towels to use at the pool on the last day ) and I always leave our inflatables behind (I buy them from our £1 shop, and they are part of our outbound luggage and don't cause a weight problem going out). We don't even have much duty-free, our last 5 holidays have been non-EU so I've been restricted to just 2 bottles of plonk which surely don't weigh more than the discarded toiletries/suncreams/lilos etc (and I've been the only adult, the kids don't get a duty free allowance, so that's 2 bottles in 3 people's weight allowance...) I just think it must be dirty clothes weighing more than clean ones...
And as for buying stuff once you're there - that's OK if it's somewhere you've been before and you know exactly where the shops are and exactly what stuff they sell. Personally I like my own shower gel and it's nice to have shower gel, toothpaste, suncreams etc to use as soon as you get there. I save my shopping trips for when I'm bored towards the end of the holiday.