If it's outside don't use acrylic, it's brittle. Use polycarbonate instead and buy roll stock off your local supplier and get it cut to size, make sure you apply your print on the correct side as it does come with UV protection on one face. There's usually a text printed on it to indicate which side has the UV protection on so you don't mess up. It's also not going to snap in half when there's a little scratch on the face and you flex it. I personally did not touch or replace any huge acrylic sign faces, the biggest ones were the really old 30+ year 2' x 4' signs on some pylons but that's about it. It's all polycarbonate nowadays, it might be called some name brand(PALSUN) at your supplier so make sure you just ask about it and tell them what you want to use it for. That's the key part, they would know best.
It also makes transport a breeze. I can fold a 27' sign into the back of a pickup truck. The hanging strips stay on too. I'm not sure what they call those from other parts of the world, the polycarbonate strips you rivet and weld onto the top and bottom faces to ensure that it stays in the channel of your extrusion even during crazy wind storms. Have to account for a little expansion and shrinkage.