There are different temperature ratings on Electrolytics.
85C and 105C
Now, most of the older TV sets and radios used the 85C parts. Often they were right next to heatsinks. They failed a lot.
This was due to the combination of heat, quality of part and the fact that many mfg. ran the capacitors to their max voltage ratings.
If you are experimenting, I think that the 85c caps are OK to use, but if it's going to be a project or repair you want to last, use the 105c rated caps and go UP one voltage rating, as insurance.
The only 2 things to going up in voltage ratings are:
1. They cost a few pennies more.
2. In a few instances, the quality, higher voltage 'lytics may be a bit larger physically than the lower voltage rated ones. I have found 98% of the time, I can easily make the higher voltage rated one work.
If you want a real eye opener, lookup the mfgr. data sheets on 'lytic types. Many only have a 1000 hr. rating before failure!!!
Yes, you can use a thru hole type in place of a smt, if you have the room, and vice versa, in a pinch. This depends on the voltage rating, of course.
As always, before use, be sure to check the 'lytic for ESR, voltage breakdown, and capacitance before installing.
NOTE:
The new digital capacitance meters do not put enough voltage out to see if a capacitor, regardless of type, fixed or 'lytic at 100v, 200v, etc. has leakage at close to the rated voltages.
Personally, I use an ESR meter- (Capacitor Wizard with the overload kit mod, as I found I can tell a lot more with a meter type ESR unit than the LED digital ones, and its useful for checking intermittent or bad solder connections too); an old Eico eye type cap meter for voltage test- (I like the one with the voltage adjustable pot, not the switched voltage ranges), and a digital capacitance meter for the high MFD ratings in the new solid state equipment.
Buy from a trusted source too. Often the "cheap import" caps are counterfeit, or way out of tolerance. They may be really old stock too, which if a 'lytic will need reforming before use.
Nothing is more irritating than buying a new part, putting it in, then spending hours of trouble shooting only to find the new part is bad. That's why I check all parts first regardless if its a capacitor, resistor, diode, xistor, etc.