To clip or not to clip. . . .

[Drnkhobo]

Is it better to have a clip module before your processing or after? Or both?

Prevent those nasty spikes and distorted signals, before they enter your schm (or just after the input) so that your processing does not go over . . . or process in excess of clipping to just clip at the end of your chain?

Anyone have an opinion?

[KG_is_back]

Theoretically you don't need to clip at all. FS uses internally 32bit float numbers which can easily represent signals out of <-1,1> range (up to 10^38). So do most DAWs - the signal gets clipped shortly before or sometimes even within your soundcard. The signal to be in <-1,1> is a convention that comes from times when int formats were used, because they can't represent values out of that range. Therefore the soundCards are calibrated so that the range fits their dynamic range.
To stay "in the crowd" you should ensure your plugin outputs values in that range (by clipping the output), and you expect other developers to follow the same rule, so you don't need to clip your input. However, since DAWs nowdays also use 32bit floats internally, no real distortion is happening (unless your plugin is specifically coded to do the distortion).
Most plugins that have volume-dependent processing involved (compressors, saturators, distortions, amp-sims, etc.) are calibrated to work best in certain range (they expect the input to be in that range and also provide output in that range). This is usually mentioned in the Manual (sometimes even on the gui of the plugin). Filters, delays and reverbs are usually volume independent (you get the same result if you boost the input and cut the output the same amount and vice versa).
It is a matter of taste how you handle this situation. I saw plugins that don't do anything with input and output, plugins that simply have volume knob both on start and end (so user handles the I/O ranges manually), plugins that clip output and even plugins that have output brickwall limiter.

[Perfect Human Interface]

Definitely don't clip as a rule. In fact, never clip unless you have a very specific reason to do so. If you want to restrict output levels, which as KG points out is often not necessary but can be especially if your processing might output spikes or high amplitudes, either use an output level knob or a limiter or both. If you use a limiter you may want to include an on-off switch.