Record the pattern safely
Note whether one post or a whole run is moving, and whether the issue followed wind, impact or a gradual change. Photograph from a stable location without pushing or testing the fence. Keep clear of sections that appear unstable.
Separate symptoms from causes
Loose connections, deteriorated components and support movement can produce similar visible lean. Simply straightening boards may not address what is happening below or around the post. The assessment should explain which components need attention and why.
Understand the repair footprint
Post work can require detaching adjacent panels and disturbing ground around the support. Discuss access, buried services and restoration. Matching weathered components may be imperfect, and unexpected damage should have an agreed change-approval process.
Choose a proportionate scope
An isolated support issue may be different from widespread deterioration. Compare a defined repair with replacement if multiple sections are affected. Do not attempt to brace a heavy unstable run without appropriate help.