Leaking Seams -- top, or bottom corners

Having had a varierty of campers over the years, the only real problem I've ever run into is the seams that sometimes leak, and once they start, don't seem to stop (pun intended). I have heard that the teardrops of the 60s and 70s had major leakage issues. Has this fault been effectively eliminated in the newer commercially made teardrops? I am not able to build my own camper due to health limitations. Thanks.
Holly
Holly