The best way to find a good glazier is to ask for recommendations amongst your family, friends and neighbours. However, if that is not possible, then look for online reviews from people who have already had glazing work done. Look out for reviews which praise customer service as hopefully those kinds of companies will do their best to overcome problems and rectify mistakes, if any should arise. Also bear in mind that some glazing firms may specialise in certain kinds of windows. For instance, you may find a company that has particular experience of replacing sash windows.
It’s a good idea to get at least 3 quotes for work to be carried out, before you make up your mind on which company to engage. The lowest price may not always be the best offer and be wary of companies that have special prices for a sale made that evening or of sales reps who phone “the manager” to obtain a special discount.
Once you have agreed to employ a glazing company, you should agree a schedule of payments before any work starts and this should appear in a written contract. It is not unusual to have to make the first payment before work starts but make sure that you only pay the final instalment once work has been completed to your satisfaction and once you have been issued with the relevant paperwork and guarantees.