1. Adhesion: A good tile adhesive has good adhesion, and can firmly adhere the tile to the floor or wall. You can check whether the back glue of the tile is evenly covered, and tap the tile gently to test its adhesion.
2. Water resistance: High-quality tile adhesive should have good water resistance and can resist water erosion in humid environment. You can choose to check the product description or consult the sales staff to understand its waterproofing.
3. Shear strength: tiles will bear certain shear force during use, and a good adhesive should have high shear strength to ensure that tiles are not easy to fall off. You can consult product specifications or test actual samples to evaluate their shear resistance.
4. Service life: High-quality adhesives should have a long service life and can maintain stable performance and adhesion. You can know the shelf life or life of the product and choose a reliable brand or manufacturer.
In addition, you can refer to other people's experience or consult professionals to get more information about the quality of tile adhesives.