Put lots of old tea tiles on the tables.....and buy ashtrays that are not damaging to your furniture.
Or you could put a coat of polyurethane varnish on the table....
But unless they have already been refinished, it will ruin the "original finish" on them.
The table under a glass top can get very messed up!

Here is a link that might be useful: tea tiles

The typical damage I've seen on table surfaces covered with glass has been moisture wicking in around the edges through capillary action from glass cleaning or spills. I've seen it done successfully. I understand what you are saying about people not respecting your good pieces. I had a relative plop his behind down on a very precious hall seat after I asked him to please not sit on it because of his size. Of course he did anyway and the repair devalued it significantly when I sold it.

Just a head's up to folks who have original table pads for some older antique dining tables. It was not uncommon for them to have asbestos in them.

For heavy ash trays, decorative bowls and such, I use those little discs with self stick backing that are made for chair legs to protect floors. They will slide on the table and not scratch..I agree, glass seems not a good idea, water does seem to be drawn under resulting in worse damage if you dont catch it right away.Also use plastic placemats,and a hawk eye...LOL

Put out coasters and if someone doesn't use one, put his/her glass on the coaster yourself!

As far as heavy stuff, I agreee with dotz-little felt dots on the bottoms of the pieces work well and don't hurt anything. Even though you didn't ask (forgive me), I would encourage smokers to go outside, though-smoke odors are hard to remove as is the brown film that gets all over the walls and furniture. :)

Friends often come up for a weekend most have no idea what a coaster is.
hmmm....party time?
You could run behind everyone, placing coasters under drinks and wiping up any moisture...but who wants to constantly do that?

You could provide an assortment of koozie cups, and place them by the iced down or cooled cans and bottles. Be prepared for a lot of them to walk off/get lost.

For sweating drinks in glasses, you could provide Styrofoam cups or buy some nice sized insulated tumblers that won't sweat.

Another option would be to either cover the entire table with flannel backed vinyl tablecloth or make runners to protect the areas most used and abused by sweating cans, bottles or glasses.

Good luck and have fun.

Sue

Sue thats the fun of a weekend home it is always party time!! Like the koozie cups, they are cheap enough that if they do walk away who cares thanks

Thats why I use plastic place mats rather than coasters at party time, they make bigger targets..:)