It's impossible to avoid all risks when investing in high-end beauty products, but you can minimize the risks by trying before you buy. I've learnt that it's the best way to judge whether the product is
 suitable for your needs or not.  I was going through my stash yesterday on a mission to throw away the 'empties' but thought I'd share with you the products I ended up buying in full-size after testing them out.
Nars Smudge Proof Base($25)
This eyeshadow primer is the best one I've ever tried, hands down. It's lightweight, translucent and dries pretty quickly once you apply it on the lids, creating a smooth surface for an eyeshadow application. Regardless of the weather, skin type, lid type- your eyeshadow will stay on all day long without creasing or budging. According to Nars, it is 'fortified with a special deep-sea extract and an antioxidant rice extract.'
Buxom Full-On Lip Creme ($19)
I think that I would've never purchased an expensive lip gloss if I haven't tried the sample from Buxom. I redeemed my Sephora's 100 points perk for a mini-size version in the shade Katie. In contrast to drugstore lip glosses, it's extremely lightweight, not sticky, and has a gentle tingling effect-not burning like Soap&Glory Lip Plumping Gloss- and has a major lasting power. The Sephora website says 'Encapsulated hyaluronic spheres infuse lips with moisture while vitamins A and E help keep them supple, protected, and extra kissable.'  Also, the great thing about these glosses is that they are formulated without parabens, sulfates, phthalates, GMOs, and triclosan. I bought one in the shade 'White Russian' which is a beautiful creamy nude pink with no shimmers-perfect for any kind of look.

I'd describe this product as a primer with long-term skincare benefits; although I haven't worn a primer for quite a while, I wanted to give this one a try since I received a deluxe sample with my purchase. It makes you skin look airbrushed and flawless once you apply makeup over it- it's suggested that you apply it over your regular moisturizer/SPF cream. It does make a noticeable difference when you apply it on your skin: the pores are visibly blurred, the texture looks more refined, and dewy. Moreover, it's paraben-free and non-comedogenic which means it'll not clog your pores. 
I love my drugstore mascaras a lot- the Maybelline Falsies in particular-but when I got a sample of They're Real mascara, I couldn't resist the urge of buying the full-size version. It does it all: volumizes, separates, lengthens your lashes and stays on all days without flaking or clumping. 
Make Up Forever 'Aqua Eyes' Eyeliner ($19)
I've been searching for a waterproof, long-lasting eyeliner for quite a while now, and I'm so glad that I've finally found the one. The Make Up Forever is well-known for it's superb line of waterproof makeup products, and their eyeliner is worth mentioning in this post. If you're looking for an eyeliner for your inner rim/waterline, the MUFE Aqua Eyes is for you. The Sephora website says: "Waterproof, highly pigmented, and smudge-proof, the Aqua collection of long-lasting lip and eye colors was created for the Parisian Aquatic Ballet. Tested under water for five hours, Make Up For Ever’s longest wearing makeup has an extensive palette of high-performance colors with non-stop results. This product is fragrance free and ophthalmologist tested." I purchased one in the shade 'Matte Black,' and couldn't be more happier with the results. 

Do you have any products that you've bought as a result of testing it out beforehand?