If the aglet (plastic bit around the tip of a shoelace) falls off and you can't lace your shoes without them, you can tightly wrap thread around them and seal it with
Abaglets Metal Aglets Shoelace Tips Metal Cord Ends Choice of 4 Colors packs of 4 - Etsy
SEWACC 100Pcs shoelace head Shoe Lace Tip Head Replacement End Metal Shoelace End shoelaces for sneakers Aglets for Shoelaces laceless laces Copper Shoelaces Tips Head protector cordless: Amazon.co.uk: Fashion
DianMan 200/40pcs Aglets Metal Aglets for Shoelaces - Shoelaces Tips DIY Shoe Lace Ends Aglet Tips for Sneaker,Hoodies,Shorts, 4 Color-200 Pcs, 4 x 18 mm : Amazon.ca: Clothing, Shoes & Accessories