No sooner then 60 days according to Maaco:
"Caring For Your New Paint
FIRST TWO WEEKS
It is best not to wash the vehicle for the first 15 days. This is a guideline and not a hard rule. If your vehicle is dirty enough to annoy you during the first couple of weeks then wash it following the guidelines below.
FIRST TWO MONTHS
Caring for your vehicle new paint job is critical for longevity. Be sure not to wax new paint as it takes about 60 days to fully cure. This will allow the finish to completely dry and cure. Your paint needs "breath" to ensure a complete cure. This is a hard rule, don't wax it during the first couple of months!
WASHING
Wash the vehicle in the shade only - Never in the sun.
Do not dry wipe the vehicle. Always use clean cool water with automotive soap. Dry wiping can cause scratching. Use plenty of water first, then wipe with a clean, wet, cotton cloth or sponge to wash off dirt. Be sure to keep the surface wet to prevent scratching.
WAXING
Always use a quality wax approved for automotive paint. Do not use silicone containing or super polymer containing waxes or polishes. Silicon-based wax penetrates all layers of paint. Today's finishes do not need such extreme protection. Removal of such waxes is very time consuming and makes touch ups difficult.
Before you wax, give your paint a good washing. Use plenty of water first, then wipe with a clean, wet, soft cotton cloth or sponge to wash off dirt. Be sure to keep the surface wet to prevent scratching. Dry with a soft chamois cloth.
It's important to keep your paint waxed, as this helps to protect the finish from minor scratches. Most waxes incorporate UV inhibitors also, which helps to protect your paint from the sun."