A qualification is not an exclusion. An exclusion says what you leave out. A qualification says what you assumed where the documents were unclear.
A flooring sub might write: price assumes slab moisture is within the limits of the adhesive manufacturer. A steel sub might write: price is based on one mobilization.
Write a qualification when a question stays open on bid day. Keep each one short and specific. Name the sheet or the spec section it relates to.
On a public hard bid, a qualified bid can be rejected as nonresponsive. Check the instructions to bidders first.