Some delay is genuinely common — weather, especially storms, can push installs back, and reputable companies do get overloaded at busy times — but going quiet is the real problem, not the delay itself. A company surviving on good customer relations should keep you informed; constant communication during a delay is a good sign, and silence after a confirmed date is a warning sign worth acting on.
If you've been pushed back repeatedly with little explanation, the suggested approach is to engage directly and calmly: request a meeting or call with the sales manager, bring your signed contract, and go through it — note the agreed dates, any commitments, and the terms around delays. That turns a vague "we're behind" into a concrete conversation about what was promised and when it'll actually happen. Storms and seasonal backlogs are legitimate reasons; a pattern of missed dates with no contact is not.
Weigh patience against your options. If the company is communicating and the delay is genuinely weather or backlog driven, sticking with them is usually fine — storm-season delays generally aren't a sign of a company being cynical. But if they've gone silent, broken multiple commitments, and won't give a straight answer, it's reasonable to reconsider, especially before any large payment changes hands. Keep everything in writing, and don't release final payment until the work is actually finished to standard.