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Top picks: PRETOLE 40th Birthday Silver Plated Interlocking Circles Necklace (best overall); Anforsun 40th Birthday Hampers for Her Pamper Gifts Basket if she needs an evening to herself; Giftasy Funny 40th Birthday 7 Oz Handmade Lavender Candle if she winds down with a candle.
A 40th can be marked with something she wears, something that helps her unwind, or a joke at the number's expense, and under £30 any of the three can be done well. Think about whether she will open it in front of a table of friends or quietly at home, and match the tone to that.
The PRETOLE necklace links four circles, one for each decade, and comes with a card that reads "4 rings for 4 fabulous decades".
Worth knowing: Skip if she only wears solid silver or gold.
Anforsun fills a rose gold gift basket with 9 items, including a 12 oz insulated tumbler, to set up a night of being looked after.
Worth knowing: Skip if she prefers one good thing to a box of small ones.
Giftasy pours this candle in natural soy wax scented with lavender and eucalyptus, and its humorous message gets a laugh before she lights it.
Worth knowing: Skip if she dislikes the smell of lavender.
The QBEJIME suncatcher pairs an engraved acrylic butterfly with a coloured crystal chain and has a loop for hanging in a window.
Worth knowing: Skip if she keeps her windows bare.