tbh I have spent way too much on gear over the years and some of it was just a total waste. I learned the hard way at a shoot last summer when my lens took a nasty bump. Unfortunately, cheap glass protectors just ruin the image quality of those nice Sigma Art optics. I tried a budget one and it was not as good as expected... it basically ruined every shot with weird ghosting and flare. Since you are doing a wedding, safety is huge. Here is what I stick with now:

• Hoya 77mm NXT Plus UV Filter
• This literally saved my front element from a scratch once. It is around 50 bucks but way cheaper than a repair.
• Peak Design Slide Camera Strap
• Those Art lenses are heavy as lead. I had issues with my neck hurting for days until I switched to this one.
• Sigma LH876-04 Lens Hood
• Keep it on always. Its basically a bumper for your glass.

I've been shooting with Sigma glass for a decade now. Early on, I remember being so frustrated because my focus was slightly off during a backyard portrait session. It drove me crazy until I realized I could just calibrate it myself. Honestly, the best thing I ever bought for my kit wasnt a filter or a bag, it was the calibration tool. It lets you update firmware too which is huge for wedding AF reliability... especially with newer bodies. Quick tip: Always calibrate your lens focus before a big event to avoid soft shots. A few items I always pack:

• Sigma USB Dock UD-11 for L-Mount
• Giottos Rocket Air Blaster Large
• B+W 82mm Master Clear MRC Nano Filter The air blaster is basically essential because those big front elements are dust magnets and you dont want to be rubbing a cloth on the glass unless you absolutely have to. Keeping the glass clear of gunk saves so much post-processing time later on.

Late to the party but like someone mentioned, calibration is a huge deal. In my experience though, weddings are just messy. I once had a flower girl smudge my front element right before the vows. I always carry the Zeiss Lens Cleaning Kit with 2oz Spray and Microfiber. Its cheap and way safer than using a t-shirt. Honestly, keeping that glass pristine during a long day is the best way to protect your investment...