Question
I live in Mansfield Texas and i was wondering if I can use Stiff linning (for sewing) as a
garden fabric for mulching, and when do I change my mulch.  

Answer
There are no rules for the type of material which compromises mulch.

The purpose of mulch is two fold: it provides a nice clean look on the flower beds, and it help preserve moisture.

Moisture is preserved as water, which would normally evaporate from the soil through capillar action. Once the moisture reaches the layer of mulch, the action is interupted and the water stays in the soil.

You can accomplish the action using any type of material which has a lighter density than soil. You can use shredded leaves, shredded hardwood bark, pine needles, straw, partially decomposed compost, etc. The benefit of these organic mulches is also that they decompose eventually and enrich the soil.

However, you do not have to use organic (biodegradable) mulches. You can use recycled shredded rubber tires, stones, broken tile pieces etc. These mulches have the benefit that they can be colored in almost hue and will last a very long time (do not need to replaced annually). Some people like the looks of stone better than shredded bark for example.

For people how grows tomatos or other similar crops and who do not mind how it looks, they will often use plastic, tarps or other mulches. They accomplish the same, but they are usually not as nice looking as the grund up mulches. This may not be important in a vegetable garden, however. The benefit of these are that they stay in one big sheet for easy removal later in the season and they keep weeds out.

If you have stiff linning (for sewing) and do not mind how it looks on the flower beds, or even like how it looks, then it is ok to use as a mulch. The requirement is that water should be able to penetrate (e.g. it should not repel water).