OPI base and top coat used to make my manicures last for 2 weeks as well, but recently I've noticed tip wear after 2-3 days! Not sure if it's the formula or my nails have changed... :(
I then switched to Seche Base and Vite and it's brilliant! I don't even have to do Chip Skip/Prep!
I use NailTek Foundation II & Seche Vite top coat.
If you tend to have shiny / oily natural nail beds, it helps to remove the natural surface oils on the nail plate by wiping the nail with rubbing alcohol (& waiting for it to dry) before applying your basecoat. You can also use a product like OPI Bond Aid, but that is mostly rubbing alcohol.