Fabric

It is highly recommended that your first suit be made of 100% wool. Wool is a natural fiber that breathes, which means you'll be more comfortable and you'll sweat less than in a suit made of man-made materials. Wool is also durable and travels well.

Fabrics other than wool have their drawbacks, and probably should not be considered for a first suit, unless there is no alternative. Polyester suits should be avoided, as they do not breathe, but if you need to keep costs down, a polyester/wool blend might be a reasonable choice.

Look for suits made of 100% "worsted" wool. The worsting process involves selecting long wool fibers and twisting them into tight and resilient yarns. Worsted wool suits are durable, hard-wearing, and usually fine for wear in all seasons.

As for the weight of the fabric, the mid-weights are best overall for year-round wear, unless you live in a very warm climate. If you do happen to live in a very warm or very cold climate, ask your salesperson about your best options in fabric weight.