No, pavers do NOT require sealer to maintain their quality.
Sealing is used to enhance or deepen the color of the pavers and to protect the surface from staining materials. If you do choose to seal, we recommend that you wait approximately 2-3 months prior to sealing to ensure no efflorescence (a whitish haze caused by naturally occurring salts used in both the base materials and/or aggregates used to manufacture the stone, that goes away with time) shows up.
If you do decide to seal, Eastern Sky recommends that you reapply the sealer every 3-6 years because it does wear over time.