1. Stainless Steel Grade: Stainless steel comes in different grades, each with different mechanical properties. For example, 304 and 316 stainless steel are two commonly used types, and 316 offers higher corrosion resistance and strength. The grade of stainless steel used for the pipes is important.

2. Pipe Size and Wall Thickness: The size and wall thickness of the pipes affect their pressure resistance. Larger diameter and thicker-walled pipes typically withstand more pressure.

3. Application Conditions: The intended application of the pipes determines the durability requirements. For instance, a pipe to be used in industrial processes may need to be more pressure-resistant.

4. Quality of Assembly and Welding: The assembly and welding processes of the pipes also affect their durability. Proper assembly and welding result in pipes that can withstand pressure more effectively.

5. Internal and External Conditions: The environmental conditions in which the pipes will be used can impact their durability. If the pipes will be exposed to abrasive substances or high temperatures, selecting the appropriate stainless steel grade is crucial.

In conclusion, the pressure resistance of stainless welded pipes depends on multiple factors, and determining how durable a specific pipe is requires engineering calculations and consideration of application specifications. Therefore, consulting with an engineer or specialist is important for choosing the right pipe and design for a particular application.