When buying a gaff, there are a few things to keep in mind to ensure that you find a high-quality, comfortable option that meets your needs. Here are some steps you can take:

1. Research: Do some research to learn about the different types of gaffs available and what features they offer. This can help you narrow down your options and find a gaff that meets your needs.
2. Check sizing: Measure your waist and hips to determine your size, and compare these measurements to the size chart provided by the manufacturer. This can help you ensure that you find a gaff that fits well and is comfortable to wear.
3. Consider style and material: Look for a gaff style and material that suits your needs and preferences. For example, you may prefer a thong style for minimal coverage, or a brief style for more coverage and support. You may also want to consider the breathability and stretchiness of the material, as well as any padding or shaping features.
4. Read reviews: Look for reviews of the gaff you're considering to see what other people have to say about it. This can help you get a sense of the quality, comfort, and durability of the gaff.
5. Buy from a reputable retailer: Look for a reputable retailer that specializes in lingerie, undergarments, or products for the LGBTQ+ community. This can help ensure that you're buying a high-quality product that meets your needs.
6. Consider a starter kit: If you're new to wearing gaffs, consider purchasing a starter kit that includes a variety of gaffs in different styles and sizes. This can help you find the right gaff for your needs and preferences, and also give you a chance to try out different styles.

By following these steps, you can find a high-quality gaff that is comfortable, supportive, and meets your needs for gender expression or other purposes.