Document what is already there
Start with clear exterior and interior photos of each window type. Note which units operate, where water staining or damaged trim is visible, and whether several openings share the same size. A basic opening list keeps the conversation organized.
Separate product decisions from installation conditions
Frame material, operating style, glass, color and grid pattern are product choices. Existing trim, sill condition, wall construction and access affect how replacement work is approached. Both sets of details matter, but they should not be confused.
Set priorities before comparing options
Decide what matters most: appearance, ease of operation, maintenance, matching the architecture, budget, or a particular project schedule. A short priority list makes material and configuration comparisons more useful.
Confirm the complete opening
For every window, confirm size, operation, handing where applicable, exterior finish and interior expectations before ordering. For grouped windows, include the full arrangement—not just individual unit sizes.
Local requirements and installation conditions vary. Confirm project-specific code, design-pressure and installation requirements with the appropriate building professional and local authority.