Some I give away, some I toss. If a rose has too much disease in my garden I expect that it just won't do well in my area, so I don't offer it. However, if it doesn't appeal to me because of a particular characteristic that another might not mind, I try to find a new home for it. I'm not always successful, but frequently I am.

Rosefolly

Like you I've a small garden and only so much room for roses. I once had ground space for 3 roses and ended up trialing 13 to see which ones I liked best. The 10 also rans were given to a couple of rose friends. Since then I've relied on other rose friends to take the ones I don't keep, but now even they have reached the saturation point. I refuse to give roses to people I know won't take care of them, so I've curtailed the number of roses I try to just one or two a year. My next step probably will be to call my local rose society to see if they will take any left over orphans I end up with in the next few years.

If they are seriously virused I throw them out. Some I find homes for. A few I manage to trade.

There's always FreeCycle or the "free" section of Craig's List.

I give them away unless they are sickly.
I'll bet there's a Rose society near you that might have an interested member.
If you're in the NW part of Washington state email me privately.
I know some people who will take them.
ridlol@msn.com.

In the past I shared (good) cast-off roses with quite a few local folks I've met here on roses forum.

I also live in a very pedestrian friendly neighborhood (near a school, church, and park) and I would leave a potted (healthy, sometimes even blooming) rose out front with a free sign and it'd be gone within hours each time.

Once I discovered rose midge a few years ago, I stopped giving away cast offs because it's just too irresponsible to risk spreading this beast. I do feel guilty destroying a rose someone else could enjoy...

I destroy mine as I also have rose midge, and don't want to spread it.

your local rose society can find homes for your unwanted but healthy roses. We have people bring in plants to meetings to be given away.

Roses with Rose Rosette Disease get bagged and go to the land fill. (And twice people have tried to give me roses with RRD.)
Roses with bad fungal problems go to the burn pile.
Roses with bacterial problems go to the burn pile if I can't cure them by cutting back.
Roses that are on a downward decline because of Rose Mosaic Viruses go to the burn pile.

I must not be a very nice person. All my cast-off roses go straight to heaven (that would be the compost area).

Healthy ones go to rose society raffles. Unhealthy ones are whacked to pieces, bagged and headed for the landfill.

My husband and I are master gardeners (seems they'll let anyone in!), and each year there is a sale to fund the county extension office. The majority of plants sold come from MG gardens, and if I have healthy roses that I don't like the look of, I donate to the sale. I think many counties have sales, though I don't know that all of them are held the right time of year for rose planting.

Lara

If they are poor performers or diseased, I pitch them. If they are healthy roses, but ones I no longer want, I put them in our local rose society auction each spring. That way people that really want them get them, and the rose society benefits.

We have another member who invites rose growers to his house to choose from among his castoffs. They are asked to make a contribution for each rose they take, and he contributes all the money to Backstoppers (the organization that supports family of deceased police and firemen).

I'm probably going to get rid of a dozen quite nice roses soon, mostly older hybrid teas, as I work to ration the water I use. I'm going to stop watering the bed they live in on a weekly basis and go down to once a month. Once I make my decision, I'll offer them to a local garden group.

For the most part I prune them, dig them up leaving as much of a "root ball" as I can and "package" them up with a note, if I know the variety, some sure start planting fertilizer and I put them on my curb with a FREE sign. I've always had takers. My best taker turned out to be a friend who knew a family that lost their mother and they were planting a memorial garden for her. Since then, I always give them first chance before I put them out on the curb. I've done this with some calla lilies that I put out with the caveat at how invasive they can become so I didn't have to feel bad if they took over. They knew what they were getting.
I've had some monster roses from the previous owner that in order to get them out I had to cut down to the ground and dig out but that is the price I had to pay to get roses in the ground that I picked.

I wish I had someome to give my sp's to, but my co-workers and neighbors are not into gardening at all. All I have ever been able to donate is bulbs and a few daylilies.
So . . . they go out in the street for trash pick-up.
Some have been duds for me and I don't feel bad, but a few I just didn't like and I know they could have pleased someone else. I took a Trumpeter from someone years ago and just love it. She only wanted cut roses. Her loss, I feel, but there is no explaining what we keep and what we sp.
I just haven't been inspired to join a rose society, although I am involved in a daylily group. When I have attended roses shows, the rose folks seemed much more serious and formal than my daylily chums. However, I may dip my toes in one of these days.
Kathy