I mainly am offering this post from the heart, to our newer fellow Hams about SOME of the oldest Rigs that you may be offered or sold!
So...Before you Buy?
Take the time to research and read the Review sections, or most certainly ask your Mentors about "SOME" of the older Rigs, out there! Many of the more experienced operators CAN advise you of HISTORICAL problems truly known, about certain Radios!
By "watch out for Drifters" I mean that some of these older Rigs (and NOT all) were quite well known to have problems with "FREQUENCY DRIFTING" meaning unstable and simply moving ON and OFF of the frequency you desire to operate on. Examples of these would be; Siltronics, Swans, some of the Kenwoods in the 120 class. Some of the older Yaesu FT101E's, Etc.
Now this remark does not imply, or state - that there are not plenty of good experienced Hams that KNOW HOW to Modify or repair some of these Rigs from operating with these problems. It simply means that if - you are a new Ham looking to purchase a starter Rig and don't have alot of money to purchase, then Repair or Modify, your first Radio?
Finding out (after you own it) the HARD WAY about such facts, will not make you a happy Camper! Ending up with many Hams telling you when you call them on the air: "Well you are not on Frequency old Man" can really put a knot in your ham radio operating pleasure.
Really...when you think about it, "sometimes" buying that Old Rig (with untold problems) along with the money you'll need to spend to repair it's problems, can easily equal the price purchasing some of the newest solid state rigs, on the market!
Don't let em talk you into buying, a modified Export CB Radio, or an old Rig of which you can't hardly even find parts for it, any longer!
FIRST - ASK - ASK - ASK.
There will always be, a great experienced Ham Mentor somewhere, that will be glad to answer your question.
8-) God Bless and 73